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SonicOS 5.9 Admin Guide

High Availability

About High Availability and Active/Active Clustering

About High Availability

This section describes how to configure and manage the High Availability feature on SonicWall security appliances.

High Availability is supported on these platforms:

NSA E5500, E6500, E7500, E8500, E8510
NSA 240, 2400, 2400MX, 3500, 4500, 5000
NSA 220 series and NSA 250M series
TZ 105 series, 200 series, 205 series, 210 series, 215 series, SOHO
* 
NOTE: The TZ 100 series is not supported
* 
NOTE: The terms Backup and Secondary are synonymous as are Standby and Idle.
Topics:

What Is High Availability?

High Availability (HA) allows two identical SonicWall security appliances running SonicOS to be configured to provide a reliable, continuous connection to the public Internet. One SonicWall device is configured as the Primary unit, and an identical SonicWall device is configured as the Secondary unit. If the Primary SonicWall fails, the Secondary SonicWall takes over to secure a reliable connection between the protected network and the Internet. Two appliances configured in this way are also known as a High Availability Pair (HA Pair).

High Availability provides a way to share SonicWall licenses between two SonicWall security appliances when one is acting as a high-availability system for the other. To use this feature, you must register the SonicWall appliances on MySonicWall as Associated Products. Both appliances must be the same SonicWall model.

High Availability Terminology

Primary - Describes the principal hardware unit itself. The Primary identifier is a manual designation, and is not subject to conditional changes. Under normal operating conditions, the Primary hardware unit operates in an Active role.
Secondary (Backup) - Describes the subordinate hardware unit itself. The Backup identifier is a relational designation, and is assumed by a unit when paired with a Primary unit. Under normal operating conditions, the Backup unit operates in an Standby mode. Upon failure of the Primary unit, the Backup unit will assume the Active role.
Active - Describes the operative condition of a hardware unit. The Active identifier is a logical role that can be assumed by either a Primary or Backup hardware unit.
Standby (Idle) - Describes the passive condition of a hardware unit. The Standby identifier is a logical role that can be assumed by either a Primary or Secondary hardware unit. The Standby unit assumes the Active role in the event of determinable failure of the Active unit.
Failover - Describes the actual process in which the Standby unit assumes the Active role following a qualified failure of the Active unit. Qualification of failure is achieved by various configurable physical and logical monitoring facilities described throughout the Task List section.
Preempt - Applies to a post-failover condition in which the Primary unit has failed, and the Secondary unit has assumed the Active role. Enabling Preempt will cause the Primary unit to seize the Active role from the Secondary after the Primary has been restored to a verified operational state.

High Availability Modes

High Availability has several operation modes, which can be selected on the High Availability > Settings page:

None—Selecting None activates a standard high availability configuration and hardware failover functionality, with the option of enabling Stateful HA and Active/Active DPI.
Active/Standby—Active/Standby mode provides basic high availability with the configuration of two identical firewalls as a High Availability Pair. The Active unit handles all traffic, while the Standby unit shares its configuration settings and can take over at any time to provide continuous network connectivity if the Active unit stops working.

By default, Active/Standby mode is stateless, meaning that network connections and VPN tunnels must be re-established after a failover. To avoid this, Stateful Synchronization can be licensed and enabled with Active/Standby mode. In this Stateful HA mode, the dynamic state is continuously synchronized between the Active and Standby units. When the Active unit encounters a fault condition, stateful failover occurs as the Standby firewall takes over the Active role with no interruptions to the existing network connections.

Active/Active DPI—The Active/Active Deep Packet Inspection (DPI) mode can be used along with the Active/Standby mode. When Active/Active DPI mode is enabled, the processor-intensive DPI services, such as Intrusion Prevention (IPS), Gateway Anti-Virus (GAV), and Anti-Spyware, are processed on the standby firewall, while other services, such as firewall, NAT, and other types of traffic, are processed on the Active firewall concurrently.
* 
NOTE: Active/Active DPI is not supported on the NSA 3600, or NSA 4600.
Active/Active Clustering—In this mode, multiple firewalls are grouped together as cluster nodes, with multiple Active units processing traffic (as multiple gateways), doing DPI and sharing the network load. Each cluster node consists of two units acting as a Stateful HA pair.

Active/Active Clustering provides Stateful Failover support in addition to load-sharing. Optionally, each cluster node can also consist of a single unit, in which case Stateful Failover and Active/Active DPI are not available.

* 
NOTE: Active/Active Clustering is supported by default on the SM 9000 series. Active/Active Clustering is supported on NSA 5600 and NSA 6600 only with the purchase of a SonicOS Expanded License. Licenses can be purchased at www.MySonicWall.com.
Active/Active DPI Clustering—This mode allows for the configuration of up to four HA cluster nodes for failover and load sharing, where the nodes load balance the application of DPI security services to network traffic. This mode can be enabled for additional performance gain, utilizing the standby units in each cluster node.

Benefits of High Availability

High Availability provides the following benefits:

Increased network reliability – In a High Availability configuration, the Secondary appliance assumes all network responsibilities when the Primary unit fails, ensuring a reliable connection between the protected network and the Internet.
Cost-effectiveness – High Availability is a cost-effective option for deployments that provide high availability by using redundant SonicWall security appliances. You do not need to purchase a second set of licenses for the Secondary unit in a High Availability Pair.
Virtual MAC for reduced convergence time after failover – The Virtual MAC address setting allows the HA Pair to share the same MAC address, which dramatically reduces convergence time following a failover. Convergence time is the amount of time it takes for the devices in a network to adapt their routing tables to the changes introduced by high availability. By default, the Virtual MAC address is provided by the SonicWall firmware and is different from the physical MAC address of either the Primary or Secondary appliances.

How Active/Standby High Availability Works

High Availability requires one SonicWall device configured as the Primary SonicWall, and an identical SonicWall device configured as the Secondary, or Secondary, SonicWall. During normal operation, the Primary SonicWall is in an Active state and the Secondary SonicWall in an Idle, or Standby, state. If the Primary device loses connectivity, the Secondary SonicWall transitions to Active mode and assumes the configuration and role of Primary, including the interface IP addresses of the configured interfaces.

Basic Active/Standby HA provides stateless high availability. After a failover to the Secondary appliance, all the pre-existing network connections must be re-established, including the VPN tunnels that must be re-negotiated. Stateful Synchronization can be licensed and enabled separately. For more information about Stateful Synchronization, see Stateful Synchronization Overview.

The failover applies to loss of functionality or network-layer connectivity on the Primary SonicWall . The failover to the Secondary SonicWall occurs when critical services are affected, physical (or logical) link failure is detected on monitored interfaces, or when the Primary SonicWall loses power. The Primary and Secondary SonicWall devices are currently only capable of performing Active/Standby High Availability or Active/Active DPI – complete Active/Active high availability is not supported at present.

For SonicWall appliances that support PortShield, High Availability requires that PortShield is disabled on all interfaces of both the Primary and Secondary appliances prior to configuring the HA Pair. Besides disabling PortShield, SonicWall security appliance configuration is performed on only the Primary SonicWall, with no need to perform any configuration on the Secondary SonicWall. The Secondary SonicWall maintains a real-time mirrored configuration of the Primary SonicWall via an Ethernet link between the designated HA ports of the appliances. If the firmware configuration becomes corrupted on the Primary SonicWall, the Secondary SonicWall automatically refreshes the Primary SonicWall with the last-known-good copy of the configuration preferences.

There are two types of synchronization for all configuration settings:

Incremental – If the timestamps are in sync and a change is made on the Active unit, an incremental synchronization is pushed to the Standby unit.
Complete –If the timestamps are out of sync and the Standby unit is available, a complete synchronization is pushed to the Standby unit. When incremental synchronization fails, a complete synchronization is automatically attempted.
Topics:

Virtual MAC Address

The Virtual MAC address allows the High Availability pair to share the same MAC address, which dramatically reduces convergence time following a failover. Convergence time is the amount of time it takes for the devices in a network to adapt their routing tables to the changes introduced by high availability.

Without Virtual MAC enabled, the Active and Standby appliances each have their own MAC addresses. Because the appliances are using the same IP address, when a failover occurs, it breaks the mapping between the IP address and MAC address in the ARP cache of all clients and network resources. The Secondary appliance must issue an ARP request, announcing the new MAC address/IP address pair. Until this ARP request propagates through the network, traffic intended for the Primary appliance’s MAC address can be lost.

The Virtual MAC address greatly simplifies this process by using the same MAC address for both the Primary and Secondary appliances. When a failover occurs, all routes to and from the Primary appliance are still valid for the Secondary appliance. All clients and remote sites continue to use the same Virtual MAC address and IP address without interruption.

By default, this Virtual MAC address is provided by the SonicWall firmware and is different from the physical MAC address of either the Primary or Secondary appliances. This eliminates the possibility of configuration errors and ensures the uniqueness of the Virtual MAC address, which prevents possible conflicts. Optionally, you can manually configure the Virtual MAC address on the High Availability > Monitoring page.

The Virtual MAC setting is available even if Stateful Synchronization is not licensed. When Virtual MAC is enabled, it is always used even if Stateful Synchronization is not enabled.

Crash Detection

The High Availability feature has a thorough self-diagnostic mechanism for both the Primary and Secondary SonicWall security appliances. The failover to the Secondary SonicWall occurs when critical services are affected, physical (or logical) link detection is detected on monitored interfaces, or when the SonicWall loses power.

The self-checking mechanism is managed by software diagnostics, which check the complete system integrity of the SonicWall device. The diagnostics check internal system status, system process status, and network connectivity. There is a weighting mechanism on both sides to decide which side has better connectivity, used to avoid potential failover looping.

Critical internal system processes such as NAT, VPN, and DHCP (among others) are checked in real time. The failing service is isolated as early as possible, and the failover mechanism repairs it automatically.

About HA Monitoring

On the High Availability > Monitoring page, you can configure both physical and logical interface monitoring. By enabling physical interface monitoring, you enable link detection for the designated HA interfaces. The link is sensed at the physical layer to determine link viability. Logical monitoring involves configuring the SonicWall to monitor a reliable device on one or more of the connected networks. Failure to periodically communicate with the device by the Active unit in the HA Pair will trigger a failover to the Standby unit. If neither unit in the HA Pair can connect to the device, no action will be taken.

The Primary and Secondary IP addresses configured on the High Availability > Monitoring page can be configured on LAN or WAN interfaces, and are used for multiple purposes:

As independent management addresses for each unit (supported on all physical interfaces)
To allow synchronization of licenses between the Standby unit and the SonicWall licensing server
As the source IP addresses for the probe pings sent out during logical monitoring

Configuring unique management IP addresses for both units in the HA Pair allows you to log in to each unit independently for management purposes. Note that non-management traffic is ignored if it is sent to one of these IP addresses. The Primary and Secondary firewalls’ unique LAN IP addresses cannot act as an active gateway; all systems connected to the internal LAN will need to use the virtual LAN IP address as their gateway.

If WAN monitoring IP addresses are configured, then X0 monitoring IP addresses are not required. If WAN monitoring IP addresses are not configured, then X0 monitoring IP addresses are required, since in such a scenario the Standby unit uses the X0 monitoring IP address to connect to the licensing server with all traffic routed via the Active unit.

The management IP address of the Secondary/Standby unit is used to allow license synchronization with the SonicWall licensing server, which handles licensing on a per-appliance basis (not per-HA Pair). Even if the Secondary unit was already registered on MySonicWall before creating the HA association, you must use the link on the System > Licenses page to connect to the SonicWall server while accessing the Secondary appliance through its management IP address.

When using logical monitoring, the HA Pair will ping the specified Logical Probe IP address target from the Primary as well as from the Secondary unit. The IP address set in the Primary IP Address or Secondary IP Address field is used as the source IP address for the ping. If both units can successfully ping the target, no failover occurs. If both cannot successfully ping the target, no failover occurs, as SonicOS will assume that the problem is with the target, and not the appliances. But, if one appliance can ping the target but the other cannot, the HA Pair will failover to the unit that can ping the target.

The configuration tasks on the High Availability > Monitoring page are performed on the Primary unit and then are synchronized automatically to the Secondary.

Stateful Synchronization Overview

This section provides an introduction to the Stateful Synchronization (Stateful High Availability) feature.

* 
NOTE: Stateful Synchronization is supported on SonicWall NSA appliances, but not on SonicWall TZ series appliances.
Topics:

What is Stateful Synchronization?

The original version of SonicOS provided a basic High Availability feature where a Secondary firewall assumes the interface IP addresses of the configured interfaces when the Primary unit fails. Upon failover, layer 2 broadcasts (ARP) are issued to inform the network that the IP addresses are now owned by the Secondary unit. All pre-existing network connections must be rebuilt. For example, Telnet and FTP sessions must be re-established and VPN tunnels must be renegotiated.

Stateful Synchronization provides dramatically improved failover performance. When enabled, the network connections and VPN tunnel information is continuously synchronized between the two units so that the Secondary can assume all network responsibilities seamlessly if the Primary appliance fails, with no interruptions to existing network connections.

Benefits of Stateful Synchronization

Stateful Synchronization provides the following benefits:

Improved reliability - By synchronizing most critical network connection information, Stateful Synchronization prevents down time and dropped connections in case of appliance failure.
Faster failover performance - By maintaining continuous synchronization between the Primary and Secondary appliances, Stateful Synchronization enables the Secondary appliance to take over in case of a failure with virtually no down time or loss of network connections.
Minimal impact on CPU performance - Typically less than 1% usage.
Minimal impact on bandwidth - Transmission of synchronization data is throttled so as not interfere with other data.

How Stateful Synchronization Works

Stateful Synchronization is not load-balancing. It is an active-standby configuration where the Primary appliance handles all traffic. When Stateful Synchronization is enabled, the Primary appliance actively communicates with the Secondary to update most network connection information. As the Primary appliance creates and updates network connection information (VPN tunnels, active users, connection cache entries, etc.), it immediately informs the Secondary appliance. This ensures that the Secondary appliance is always ready to transition to the Active state without dropping any connections.

The synchronization traffic is throttled to ensure that it does not interfere with regular network traffic. All configuration changes are performed on the Primary appliance and automatically propagated to the Secondary appliance. The High Availability pair uses the same LAN and WAN IP addresses—regardless of which appliance is currently Active.

When using SonicWall Global Management System (GMS) to manage the appliances, GMS logs into the shared WAN IP address. In case of a failover, GMS administration continues seamlessly, and GMS administrators currently logged into the appliance will not be logged out, however Get and Post commands may result in a timeout with no reply returned.

The following table lists the information that is synchronized and information that is not currently synchronized by Stateful Synchronization.

 

Synchronized and Not Synchronized Information

Information that is Synchronized

Information that is not Synchronized

VPN information

Dynamic WAN clients (L2TP, PPPoE, and PPTP)

Basic connection cache

Deep Packet Inspection (GAV, IPS, and Anti Spyware)

FTP

IPHelper bindings (such as NetBIOS and DHCP)

Oracle SQL*NET

SYNFlood protection information

Real Audio

Content Filtering Service information

RTSP

VoIP protocols

GVC information

Dynamic ARP entries and ARP cache time outs

Dynamic Address Objects

Active wireless client information

DHCP server information

wireless client packet statistics

Multicast and IGMP

Rogue AP list

Active users

ARP

SonicPoint status

Wireless guest status

License information

Weighted Load Balancing information

RIP and OSPF information

Topics:
Security Services and Stateful Synchronization

High Availability pairs share a single set of security services licenses and a single Stateful HA license. These licenses are synchronized between the Active and Standby appliances in the same way that all other information is synchronized between the two appliances. For information on license synchronization, see High Availability License Synchronization Overview.

Stateful Synchronization Example

Sample Stateful Synchronization Network shows a sample Stateful Synchronization network.

Sample Stateful Synchronization Network

In case of a failover, this sequence of events occurs:

1
A PC user connects to the network, and the Primary SonicWall security appliance creates a session for the user.
2
The Primary appliance synchronizes with the Secondary appliance. The Secondary now has all of the user’s session information.
3
The power is unplugged from the Primary appliance and it goes down.
4
The Secondary unit does not receive heartbeat messages from the Primary appliance and switches from Standby to Active mode.
5
The Secondary appliance begins to send gratuitous ARP messages to the LAN and WAN switches using the same Virtual MAC address and IP address as the Primary appliance. No routing updates are necessary for downstream or upstream network devices.
6
When the PC user attempts to access a Web page, the Secondary appliance has all of the user’s session information and is able to continue the user’s session without interruption.

Active/Active DPI HA Overview

* 
NOTE: Active/Active DPI requires Stateful Synchronization and is supported on SonicWall E-Class NSA appliances.
Topics:

What is Active/Active DPI HA?

The High Availability feature on versions of SonicOS prior to 5.5 uses an active-standby model that requires the active firewall to perform all DPI, firewall, NAT, and other processing, while the standby firewall is not utilized until failover occurs. In an active/active model, both firewalls share the processing.

With Active/Active DPI enabled on a Stateful HA pair, the Deep Packet Inspection (DPI) services are processed on the standby firewall of an HA pair concurrently with the processing of firewall, NAT, and other modules on the active firewall. The following DPI services are affected:

Gateway Anti-Virus (GAV)
Anti-Spyware
Intrusion Protection (IPS)
Application Firewall

When Active/Active DPI is enabled on a Stateful HA pair, these DPI services can be processed concurrently with firewall, NAT, and other modules on both the active and standby firewalls. Processing of all modules other than DPI services is restricted to the active unit.

Benefits of Active/Active DPI HA

Active/Active DPI taps into the unused CPU cycles available in the standby unit, but the traffic still arrives and leaves through the active unit. The standby unit only sees the network traffic offloaded by the active unit, and processing of all modules other than DPI services is restricted to the active unit. The benefits of the Active/Active DPI feature include the following:

Both the firewalls in the HA pair are utilized to derive maximum throughput
GAV, IPS, Anti-Spyware, and Application Firewall services are the most processor intensive, and concurrent processing of these services on the standby firewall while the active firewall performs other processing provides the most throughput gain

How Does Active/Active DPI Work?

To use the Active/Active DPI feature, you must configure an additional interface as the Active/Active DPI Interface. For example, if you choose to make X5 the Active/Active DPI Interface, you must physically connect X5 on the active unit to X5 on the standby unit in the HA pair. Certain packet flows on the active unit are selected and offloaded to the standby unit on the Active/Active DPI Interface. DPI is performed on the standby unit, and then the results are returned to the active unit over the same interface. The remaining processing is performed on the active unit.

After configuring Stateful Synchronization on the appliances in the HA pair, connecting and configuring the HA data interface is the only additional configuration required to enable Active/Active DPI.

Prerequisites

Topics:
* 
NOTE: High Availability is only supported on the SonicWall security appliances listed in Licensing by Platform.

The prerequisites for Active/Active Clustering are described in Active/Active Clustering Prerequisites.

For a high-level configuration task list, see Configuration Task List.

Active/Standby and Active/Active DPI Prerequisites

Licensing requirements by platform is described in Licensing by Platform.

Stateful and Non-Stateful Synchronization Prerequisites

Your network environment must meet the following prerequisites before configuring Stateful Synchronization or non-Stateful Synchronization:

The Primary and Secondary appliances must be the same model. Mixing and matching SonicWalls of different hardware types is not currently supported.
It is strongly recommended that the Primary and Secondary appliances run the same version of SonicOS firmware; system instability may result if firmware versions are out of sync, and all High Availability features may not function completely.
On SonicWall appliances that support the PortShield feature ( SonicWall TZ series and NSA 240), High Availability can only be enabled if PortShield is disabled on all interfaces of both the Primary and Secondary appliances.
Both units must be registered and associated as a High Availability pair on MySonicWall before physically connecting them.
The WAN virtual IP address and interfaces must use static IP addresses.
* 
NOTE: SonicWall High Availability cannot be configured using the built-in wireless interface, nor can it be configured using Dynamic WAN interfaces.

SonicWall High Availability does not support dynamic IP address assignment from your ISP.

Three LAN IP addresses are required:
LAN Virtual IP Address - Configured on the X0 interface of the Primary unit. This is the default gateway for all devices configured on the LAN. Accessing the management interface with this IP address will log you into the appliance that is Active whether it is the Primary unit or Secondary unit.
Primary LAN Management IP Address - Configured under High Availability > Monitoring. This is the IP address used for managing the Primary unit over the LAN interface, regardless of the Active or Standby status of the unit.
Secondary LAN Management IP Address - Configured under High Availability > Monitoring. This is the IP address used for managing the Secondary unit over the LAN interface, regardless of the Active or Standby status of the unit.
At least one WAN IP address is required:
WAN Virtual IP Address - Configured on the X1 Interface of the Primary unit. Accessing the management interface with this IP address will log you into the appliance that is Active whether it is the Primary unit or Secondary unit
Primary WAN Management IP Address (Optional) - Configured under High Availability > Monitoring. This is the IP address used for managing the Primary unit over the WAN interface, regardless of the Active or Standby status of the unit. This requires that you have an additional routable IP address available. This is optional, as you can always manage the Active unit with one static WAN IP address.
Secondary WAN Management IP Address (Optional) - Configured under High Availability > Monitoring. This is the IP address used for managing the Secondary unit over the WAN interface, regardless of the Active or Standby status of the unit. This requires that you have an additional routable IP address available. This is optional, as you can always manage the Active unit with one static WAN IP address.
* 
NOTE: If using only a single WAN IP, the Secondary device, when in Standby mode, will not be able to use NTP to synchronize its internal clock.

When HA Monitoring/Management IP addresses are configured only on WAN interfaces, they need to be configured on all the WAN interfaces for which a Virtual IP address has been configured.

If you will not be using Primary/Secondary WAN Management IP address, make sure each entry field is set to 0.0.0.0 (in the High Availability > Monitoring page) – the SonicWall will report an error if the field is left blank.

* 
NOTE: If each SonicWall has a Primary/Secondary WAN Management IP address for remote management, the WAN IP addresses must be in the same subnet. If shifting a previously assigned interface to act as a unique WAN interface, be sure to remove any custom NAT policies that were associated with that interface before configuring it.

Physically Connecting Your Appliances

* 
NOTE: For complete procedures for connecting your appliances, see the Getting Started Guide for your appliance. For procedures for connecting Active/Active Cluster appliances, see Physically Connecting Your Active/Active Cluster Appliances.

If you are connecting the Primary and Secondary appliances to an Ethernet switch that uses the spanning tree protocol, be aware that it may be necessary to adjust the link activation time on the switch port to which the SonicWall interfaces connect. For example, on a Cisco Catalyst-series switch, it is necessary to activate spanning tree port fast for each port connecting to the SonicWall security appliance’s interfaces.

High Availability requires additional physical connections among the affected SonicWall appliances.For all modes, you need connections for HA Control and HA Data. Active/Active DPI requires an additional connection.

In any High Availability deployment, you must physically connect the LAN and WAN ports of all units to the appropriate switches.

It is important that the X0 interfaces from all units be connected to the same broadcast domain. Otherwise, traffic failover will not work. Also, X0 is the default redundant HA port; in case the normal HA Control link fails, X0 is used to communicate heartbeats between units. Without X0 in the same broadcast domain, both units would become active if the HA Control link fails.

A WAN connection to the Internet is useful for registering your appliances on MySonicWall and for synchronizing licensing information. Unless live communication with SonicWall's licensing server is not permitted due to network policy, the WAN (X1) interface should be connected before registration and licensing are performed.

SonicWall network security appliances requires the following interface link speeds for each designated HA interface:

HA Control Interface—Can be a 1GB or 10GB interface. 1GB is recommended.
Link Aggregation and Port Redundancy are not supported for the HA Control Interface.
HA Data Interface—Can be a 1GB or 10GB interface. 10GB is recommended. The HA Control Interface and the HA Data Interface can share the same single interface. If they share a single interface, 10GB is recommended.
Active/Active DPI Interface—Can be a 1GB or 10GB interface.

Initial High Availability Setup

Before you begin the configuration of High Availability on the Primary SonicWall security appliance, perform the following initial setup procedures.

Register and associate the Primary and Secondary SonicWall security appliances as a High Availability pair on MySonicWall. See Licensing High Availability Features.
On the back of the Secondary SonicWall security appliance, locate the serial number and write the number down. You need to enter this number in the High Availability > Settings page.
Make sure that the two appliances are running the same SonicOS Enhanced versions.
Make sure Primary SonicWall and Secondary SonicWall security appliance’s LAN, WAN, and other interfaces are properly configured for seamless failover.
Connect the Primary SonicWall and Secondary SonicWall appliances with a CAT5 or CAT6-rated crossover cable. The Primary and Secondary SonicWall security appliances must have a dedicated connection between each other for High Availability. SonicWall recommends cross-connecting the two together using a CAT5/6 crossover Ethernet cable, but a connection using a dedicated 100Mbps hub/switch is also acceptable.

High Availability Interfaces by Platform shows which interface to use for the various SonicWall security appliance platforms.

 

High Availability Interfaces by Platform

Platform

Interface for High Availability

NSA E5500, E6500, E7500, E8500, E8510

HA port

NSA 2400, 3500, 4500, 5000

X5

NSA 2400MX

X25

NSA 250M, 250M Wireless

X4

NSA 240

X8

NSA 220, 220 Wireless

X6

SOHO

X4

TZ 210, TZ 210 Wireless-N

X6

TZ 205, 205W

X4

TZ 200, TZ 200 Wireless-N

X4

TZ 105, 105 Wireless

X4

TZ 100, 100W

Not supported

Power on the Primary appliance, and then power on the Secondary appliance.
Do not make any configuration to the Primary’s High Availability interface; the High Availability programming in an upcoming step takes care of this issue. See Configuring Active/Standby High Availability Settings or Configuring Active/Active DPI High Availability Settings. When done, disconnect the workstation.

Maintenance

Topics:

Removing an HA Association

You can remove the association between two SonicWall security appliances on MySonicWall at any time. You might need to remove an existing HA association if you replace an appliance or reconfigure your network. For example, if one of your SonicWall security appliances fails, you will need to replace it. Or, you might need to switch the HA Primary appliance with the Secondary, or HA Secondary, unit after a network reconfiguration. In either case, you must first remove the existing HA association and then create a new association that uses a new appliance or changes the parent-child relationship of the two units.

See Replacing a SonicWall Security Appliance.

To remove the association between two registered SonicWall security appliances:
1
Login to MySonicWall.
2
In the left navigation bar, click My Products.
3
On the My Products page, under Registered Products, scroll down to find the secondary appliance from which you want to remove associations. Click the product name or serial number.
4
On the Service Management - Associated Products page, scroll down to the Parent Product section, just above the Associated Products section.
5
Under Parent Product, to remove the association for this appliance:
a
Click Remove.
b
Wait for the page to reload.
c
Scroll down.
d
Click Remove again.

Replacing a SonicWall Security Appliance

If your SonicWall security appliance has a hardware failure while still under warranty, SonicWall will replace it. In this case, you need to remove the HA association containing the failed appliance in MySonicWall, and add a new HA association that includes the replacement. If you contact SonicWall Technical Support to arrange the replacement (known as an RMA), Support will often take care of this for you.

After replacing the failed appliance in your equipment rack with the new unit, you can update MySonicWall and your SonicOS configuration.

Replacing a failed HA Primary unit is slightly different than replacing an HA Secondary unit. Both procedures are provided in these sections:

Replacing an HA Primary Unit
To replace an HA Primary unit:
1
In the SonicOS management interface of the remaining SonicWall security appliance (the Secondary unit), on the High Availability screen, uncheck Enable High Availability to disable it.
2
Check Enable High Availability.

The old Secondary unit now becomes the Primary unit. Its serial number is automatically displayed in the Primary SonicWall Serial Number field.

3
Type the serial number for the replacement unit into the Secondary SonicWall Serial Number field.
4
Click Synchronize Settings.
5
On MySonicWall, remove the old HA association. See Removing an HA Association.
6
On MySonicWall, register the replacement SonicWall security appliance and create an HA association with the new Primary (original Secondary) unit as the HA Primary, and the replacement unit as the HA Secondary. See Registering and Associating Appliances on MySonicWall.
7
Contact SonicWall Technical Support to transfer the security services licenses from the former HA Pair to the new HA Pair.

This step is required when the HA Primary unit has failed, because the licenses are linked to the Primary unit in an HA Pair.

Replacing an HA Secondary Unit
To replace an HA Secondary unit:
1
On MySonicWall, remove the old HA association. See Removing an HA Association.
2
On MySonicWall, register the replacement SonicWall security appliance .
3
Create an HA association with the original HA Primary, using the replacement unit as the HA Secondary. See Replacing an HA Primary Unit.

Licensing

Topics:

Licensing High Availability Features

Active/Active Clustering, Stateful High Availability, and Active/Active DPI licenses are included on registered firewalls. So, you do not need to purchase any additional licenses to use these High Availability features.

* 
NOTE: Active/Active Clustering and Stateful High Availability licenses must be activated on each appliance, either by registering the unit on MySonicWall from the SonicOS management interface, or by applying the license keyset to each unit if Internet access is not available.

You can view system licenses on the System > Licenses page of the management interface. This page also provides a way to log into MySonicWall.

When the firewalls in the Active/Active cluster have Internet access, each appliance in the cluster must be individually registered from the SonicOS management interface while the administrator is logged into the individual management IP address of each appliance. This allows the Secondary units to synchronize with the SonicWall licensing server and share licenses with the associated Primary appliances in each HA pair.

There is also a way to synchronize licenses for an HA pair whose appliances do not have Internet access. When live communication with SonicWall's licensing server is not permitted due to network policy, you can use license keysets to manually apply security services licenses to your appliances. When you register a firewall on MySonicWall, a license keyset is generated for the appliance. If you add a new security service license, the keyset is updated. However, until you apply the licenses to the appliance, it cannot perform the licensed services.

* 
NOTE: In a High Availability deployment without Internet connectivity, you must apply the license keyset to both of the appliances in the HA pair.
Topics:
Licensing by Platform

Licenses Available by Platform shows the HA licenses that are included with the purchase of the SonicWall network security appliance. Some platforms require additional licensing to use the Stateful Synchronization or Active/Active DPI features. SonicOS Expanded licenses or High Availability licenses can be purchased on MySonicWall or from a SonicWall reseller.

 

Licenses Available by Platform

Platform

Stateful Synchronization

Active/Active DPI

NSA 2600

Expanded license or HA license

N/A

NSA 3600

Expanded license or HA license

N/A

NSA 4600

Included

N/A

NSA 5600

Included

Expanded

A7014414

NSA 6600

Included

Expanded

A7014415

SM 9200

Included

Included

SM 9400

Included

Included

SM 9600

Included

Included

You can use one of these procedures to apply licenses to an appliance:

Activating Licenses from the SonicOS User Interface

Follow the procedure in Activating, Upgrading, or Renewing Services to activate licenses from within the SonicOS user interface. Perform the procedure for each of the appliances in a High Availability Pair while logged into its individual LAN management IP address.

See High Availability > Monitoring for information about configuring individual IP addresses.

High Availability License Synchronization Overview

Topics:
What is High Availability License Synchronization?

High Availability license synchronization provides a way to share SonicWall security services, Stateful Synchronization, and other licenses between two SonicWall security appliances when one is acting as a high availability secondary for the other. To use this feature, you must register the SonicWall appliances on mySonicWall.com as Associated Products. Both appliances must be the same SonicWall model.

High availability license synchronization allows sharing of the SonicOS Enhanced license, the Support subscription, and the security services licenses present on the Primary SonicWall appliance with the associated Secondary appliance. All security services you see on the Security Services > Summary page are shareable, including Free Trial services. The only licenses that are not shareable are for consulting services, such as the SonicWall GMS Preventive Maintenance Service. When a hardware failover occurs, the Secondary appliance is licensed and ready to take over network security operations.

In SonicOS 4.0 and higher, the Stateful Synchronization Upgrade is offered on appliance models that support it as an optional licensed feature. On MySonicWall, only the Primary unit in the HA pair needs to be licensed. With Stateful Synchronization the Primary unit actively communicates with the Secondary on a per connection and VPN level. As the Primary creates and updates connection cache entries or VPN tunnels, the Secondary unit is informed of such changes. The Secondary unit remains in a continuously synchronized state so that it can seamlessly assume the network responsibilities upon failure of the Primary unit with no interruption to existing network connections.

Benefits

High Availability license synchronization is a cost-effective option for deployments that provide high availability by using redundant SonicWall security appliances. You do not need to purchase a second set of licenses for the Standby unit in a High Availability pair. When the Stateful Synchronization Upgrade is licensed, the Secondary unit is always synchronized so that there is no interruption to existing network connections if the Primary unit fails.

Active/Active Clustering

This section provides conceptual information and describes how to configure and use the Active/Active Clustering feature.

Topics:

What is Active/Active Clustering?

An Active/Active Cluster is formed by a collection of Cluster Nodes. A Cluster Node can consist of a Stateful HA pair, a Stateless HA pair or a single standalone unit. Dynamic state synchronization is only available in a Cluster Node if it is a Stateful HA pair. The traditional SonicWall High Availability protocol or Stateful HA protocol is used for communication within the Cluster Node, between the units in the HA pair.

When a Cluster Node is a Stateful HA pair, Active/Active DPI can be enabled within the Cluster Node for higher performance.

With Active/Active Clustering, you can assign certain traffic flows to each node in the cluster, providing load sharing in addition to redundancy, and supporting a much higher throughput without a single point of failure.

A typical recommended setup includes four firewalls of the same SonicWall model configured as two Cluster Nodes, where each node consists of one Stateful HA pair. For larger deployments, the cluster can include eight firewalls, configured as four Cluster Nodes (or HA pairs). Within each Cluster Node, Stateful HA keeps the dynamic state synchronized for seamless failover with zero loss of data on a single point of failure. Stateful HA is not required, but is highly recommended for best performance during failover.

Load sharing is accomplished by configuring different Cluster Nodes as different gateways in your network. Typically this is handled by another device downstream (closer to the LAN devices) from the Active/Active Cluster, such as a DHCP server or a router.

A Cluster Node can also be a single firewall, allowing an Active/Active cluster setup to be built using two firewalls. In case of a fault condition on one of the firewalls in this deployment, the failover is not stateful as neither firewall in the Cluster Node has an HA Secondary.

Redundancy is achieved at several levels with Active/Active Clustering:

The cluster provides redundant Cluster Nodes, each of which can handle the traffic flows of any other Cluster Node, if a failure occurs.
The Cluster Node consists of a Stateful HA pair, in which the Secondary firewall can assume the duties of the Primary unit in case of failure.
Port redundancy, in which an unused port is assigned as a secondary to another port, provides protection at the interface level without requiring failover to another firewall or node.
Active/Active DPI can be enabled, providing increased throughput within each Cluster Node.
Topics:

Examples

Topics:
Active/Active Clustering – Four-Unit Deployment

Active/Active Clustering: Four-Unit Deployment

Active/Active Clustering: Four-Unit Deployment shows a four-unit cluster. Each Cluster Node contains one HA pair. The designated HA ports of all four appliances are connected to a Layer 2 switch. These ports are used for:

Cluster Node management
Monitoring state messages sent over SonicWall Virtual Router Redundancy Protocol (SVRRP)
Configuration synchronization

The two units in each HA pair are also connected to each other using another interface (shown as the Xn interface). This is the Active/Active DPI Interface necessary for Active/Active DPI. With Active/Active DPI enabled, certain packets are offloaded to the standby unit of the HA pair for DPI processing.

For more information about physically connecting redundant ports and redundant switches, see the Active/Active Clustering Full Mesh Deployment Technote.

Active/Active Clustering – Two-Unit Deployment

Active/Active Clustering: Two-Unit Deployment

Active/Active Clustering: Two-Unit Deployment shows a two-unit cluster. In a two-unit cluster, HA pairs are not used. Instead, each Cluster Node contains a single appliance. The designated HA ports on the two appliances are connected directly to each other using a cross-over cable. The SVRRP uses this HA port connection to send Cluster Node management and monitoring state messages. SVRRP management messages are initiated on the Master Node, and monitoring information is communicated from every appliance in the cluster. The HA port connection is also used for configuration synchronization between Cluster Nodes.

Benefits of Active/Active Clustering

All the firewalls in the cluster are utilized to derive maximum throughput
Can run in conjunction with Active/Active DPI to perform concurrent processing of IPS, GAV, Anti-Spyware, and Application Firewall services, which are the most processor intensive, on the standby firewall in each HA pair while the active firewall performs other processing
Load sharing is supported by allowing the assignment of particular traffic flows to each node in the cluster
All nodes in the cluster provide redundancy for the other nodes, handling traffic as needed if other nodes go down
Interface redundancy provides backup for traffic flow without requiring failover
Both Full Mesh and non-Full Mesh deployments are supported

How Does Active/Active Clustering Work?

There are several important concepts to know about Active/Active Clustering.

Topics:

About Cluster Nodes

An Active/Active Cluster is formed by a collection of Cluster Nodes. A Cluster Node can consist of a:

Stateful HA pair
Stateless HA pair
Single standalone unit

Dynamic state synchronization is only available in a Cluster Node if it is a Stateful HA pair. The traditional SonicWall High Availability protocol or Stateful HA protocol is used for communication within the Cluster Node, between the units in the HA pair.

When a Cluster Node is a Stateful HA pair, Active/Active DPI can be enabled within the Cluster Node for higher performance.

About the Cluster

All devices in the Cluster must be of same product model and be running the same firmware version.

Within the cluster, all units are connected and communicating with each other. For physical connectivity, the designated HA ports of all the units in the cluster must be connected to the same Layer 2 network. For communication between Cluster Nodes, a new protocol called SonicWall Virtual Router Redundancy Protocol (SVRRP) is used. Cluster Node management and monitoring state messages are sent using SVRRP.

All Cluster Nodes share the same configuration, which is synchronized by the Master Node. The Master Node is also responsible for synchronizing firmware to the other nodes in the cluster. The HA port connection is used to synchronize configuration and firmware updates.

Dynamic state is not synchronized across Cluster Nodes, but only within a Cluster Node. When a Cluster Node contains an HA pair, Stateful HA can be enabled within that Cluster Node, with the advantages of dynamic state synchronization and stateful failover as needed. In the event of the failure of an entire Cluster Node, the failover will be stateless. This means that pre-existing network connections must be rebuilt. For example, Telnet and FTP sessions must be re-established and VPN tunnels must be renegotiated.

* 
NOTE: About Failover provides more information about how failover works.

The maximum number of Cluster Nodes in a cluster is currently limited to four. If each Cluster Node is an HA pair, the cluster includes eight firewalls.

Actions Allowed Within the Cluster

The types of administrative actions that are allowed differ based on the state of the firewall in the cluster. All actions are allowed for admin users with appropriate privileges on the active firewall of the Master Node, including all configuration actions. A subset of actions are allowed on the active firewall of Non-Master nodes, and even fewer actions are allowed on firewalls in the standby state.

Administrative Actions for Active Firewalls lists the allowed actions for active firewalls of Non-Master nodes and standby firewalls in the cluster.

 

Administrative Actions for Active Firewalls

Administrative Action

Active Non-Master

Standby

Read-only actions

Allowed

Allowed

Registration on MySonicWall

Allowed

Allowed

License Synchronization with SonicWall License Manager

Allowed

Allowed

Diagnostic tools in System > Diagnostics

Allowed

Allowed

Packet capture

Allowed

Allowed

HA Synchronize Settings (syncs settings to the HA peer within the node)

Allowed

Not allowed

HA Synchronize Firmware (syncs firmware to the HA peer within the node)

Allowed

Not allowed

Administrative logout of users

Allowed

Not allowed

Authentication tests (such as test LDAP, test RADIUS, test Authentication Agent)

Allowed

Not allowed

About Virtual Groups

Active/Active Clustering also introduces the concept of Virtual Groups. Currently, a maximum of four Virtual Groups are supported.

A Virtual Group is a collection of virtual IP addresses for all the configured interfaces in the cluster configuration (unused/unassigned interfaces do not have virtual IP addresses). When Active/Active Clustering is enabled for the first time, the configured IP addresses for the interfaces on that firewall are converted to virtual IP addresses for Virtual Group 1. Thus, Virtual Group 1 will include virtual IP addresses for X0, X1, and any other interfaces which are configured and assigned to a zone.

A Virtual Group can also be thought of as a logical group of traffic flows within a failover context, in that the logical group of traffic flows can failover from one node to another depending upon the fault conditions encountered. Each Virtual Group has one Cluster Node acting as the owner and one or more Cluster Nodes acting as standby. A Virtual Group is only owned by one Cluster Node at a time, and that node becomes the owner of all the virtual IP addresses associated with that Virtual Group. The owner of Virtual Group 1 is designated as the Master Node, and is responsible for synchronizing configuration and firmware to the other nodes in the cluster. If the owner node for a Virtual Group encounters a fault condition, one of the standby nodes will become the owner.

As part of the configuration for Active/Active Clustering, the serial numbers of other firewalls in the cluster are entered into the SonicOS management interface, and a ranking number for the standby order is assigned to each. When the Active/Active Clustering configuration is applied, up to three additional Virtual Groups are created, corresponding to the additional Cluster Nodes added, but virtual IP addresses are not created for these Virtual Groups. You need to configure these virtual IP addresses on the Network > Interfaces page.

There are two factors in determining Virtual Group ownership (which Cluster Node owns which Virtual Group):

Rank of the Cluster Node – The rank is configured in the SonicOS management interface to specify the priority of each node for taking over the ownership of a Virtual Group.
Virtual Group Link Weight of the Cluster Nodes – This is the number of interfaces in the Virtual Group that are up and have a configured virtual IP address.

When more than two Cluster Nodes are configured in a cluster, these factors determine the Cluster Node that is best able to take ownership of the Virtual Group. In a cluster with two Cluster Nodes, one of which has a fault, naturally the other will take ownership.

SVRRP is used to communicate Virtual Group link status and ownership status to all Cluster Nodes in the cluster.

The owner of Virtual Group 1 is designated as the Master Node. Configuration changes and firmware updates are only allowed on the Master Node, which uses SVRRP to synchronize the configuration and firmware to all the nodes in the cluster. On a particular interface, virtual IP addresses for Virtual Group 1 must be configured before other Virtual Groups can be configured.

Topics:
Load Sharing and Multiple Gateway Support

The traffic for the Virtual Group is processed only by the owner node. A packet arriving on a Virtual Group will leave the firewall on the same Virtual Group. In a typical configuration, each Cluster Node owns a Virtual Group, and therefore processes traffic corresponding to one Virtual Group.

This Virtual Group functionality supports a multiple gateway model with redundancy. In a deployment with two Cluster Nodes, the X0 Virtual Group 1 IP address can be one gateway and the X0 Virtual Group 2 IP address can be another gateway. It is up to the network administrator to determine how the traffic is allocated to each gateway. For example, you could use a smart DHCP server which distributes the gateway allocation to the PCs on the directly connected client network, or you could use policy based routes on a downstream router.

When Active/Active Clustering is enabled, the SonicOS internal DHCP server is turned off and cannot be enabled. Networks needing a DHCP server can use an external DHCP server which is aware of the multiple gateways, so that the gateway allocation can be distributed.

* 
NOTE: When Active/Active Clustering is enabled, the SonicOS internal DHCP server is turned off.
Effect on Related Configuration Pages

When Active/Active Clustering is initially enabled, the existing IP addresses for all configured interfaces are automatically converted to virtual IP addresses for Virtual Group 1. When Virtual Group 1 or any Virtual Group is created, default interface objects are created for virtual IP addresses with appropriate names, such as Virtual Group 1 or Virtual Group 2. The same interface can have multiple virtual IP addresses, one for each Virtual Group that is configured. You can view these virtual IP addresses in the Network > Interfaces page.

* 
NOTE: All Cluster Nodes in the Active/Active cluster share the same configuration

A virtual MAC address is associated with each virtual IP address on an interface and is generated automatically by Sonic OS. The virtual MAC address is created in the format 00-17-c5-6a-XX-YY, where XX is the interface number such as 03 for port X3, and YY is the internal group number such as 00 for Virtual Group 1, or 01 for Virtual Group 2.

* 
NOTE: The Active/Active virtual MAC address is different from the High Availability virtual MAC address. The High Availability virtual MAC address functionality is not supported when Active/Active Clustering is enabled.

NAT policies are automatically created for the affected interface objects of each Virtual Group. These NAT policies extend existing NAT policies for particular interfaces to the corresponding virtual interfaces. You can view these NAT policies in the Network > NAT Policies page. Additional NAT policies can be configured as needed and can be made specific to a Virtual Group if desired.

After Active/Active Clustering is enabled, you must select the Virtual Group number during configuration when adding a VPN policy.

About SVRRP

For communication between Cluster Nodes in an Active/Active cluster, a new protocol called SonicWall Virtual Router Redundancy Protocol (SVRRP) is used. Cluster Node management and monitoring state messages are sent using SVRRP over the HA port connection.

SVRRP is also used to synchronize configuration changes, firmware updates, and signature updates from the Master Node to all nodes in the cluster. In each Cluster Node, only the active unit processes the SVRRP messages.

In the case of failure of the HA port connection, SVRRP heartbeat messages are sent on the X0 interface. However, while the HA port connection is down, configuration is not synchronized. Firmware or signature updates, changes to policies, and other configuration changes cannot be synchronized to other Cluster Nodes until the HA port connection is fixed.

About Redundant Ports and Redundant Switches

Redundant port capability is provided when Active/Active Clustering is enabled. If one port should have a fault, the traffic is seamlessly handled through the redundant port without causing an HA or Active/Active failover. A Redundant Port field in the Network > Interfaces > Edit Interface dialog becomes available when Active/Active Clustering is enabled.

When configuring a redundant port, the interface must be unused; that is, not assigned to any zone. The two ports must be physically connected to the same switch, or preferably, to redundant switches in the network.

* 
NOTE: Because all Cluster Nodes shares the same configuration, each node must have the same redundant ports configured and connected to the same switch(es).

While all Cluster Nodes are up and processing traffic normally, redundant ports remain standby and are ready for use if the partner port goes down for any reason. If one Cluster Node goes down, causing an Active/Active failover, the redundant port on the remaining Cluster Node is put to use immediately to handle the traffic for the Virtual Group that was owned by the failed node. This provides load sharing.

For example, say we have a deployment in which Virtual Group 1 is owned by Cluster Node 1 and Virtual Group 2 is owned by Cluster Node 2. The Cluster Nodes are configured with redundant ports, X3 and X4. No traffic is sent on X4 while all nodes are functioning properly. If Cluster Node 2 goes down, Virtual Group 2 is now also owned by Cluster Node 1. At this point, the redundant port X4 begins to be used for load sharing. Virtual Group 1 traffic is sent on X3, while Virtual Group 2 traffic is sent on X4. In a larger deployment, if Cluster Node 1 owns three or four Virtual Groups, traffic is distributed among the redundant ports – traffic for Virtual Groups 1 & 3 is sent on X3, while traffic for Virtual Groups 2 & 4 is sent on X4.

When a redundant switch is configured, SonicWall recommends using a redundant port to connect to it. While it is possible to connect a redundant switch without using a redundant port, this involves complex configuration using probes. A redundant switch can be deployed anywhere in the network depending on the need for high availability. For example, a redundant switch might be deployed on the WAN side if traffic passing through it is business-critical.

Deployment with Redundant Routers, Switches, and Ports shows a deployment that includes redundant routers, switches, and ports on the WAN side, but is not a Full Mesh deployment because the LAN side does not use redundancy.

Deployment with Redundant Routers, Switches, and Ports

Full Mesh is not required when deploying redundant ports or switches, but a Full Mesh deployment includes them. A Full Mesh deployment uses redundant ports on each of the main traffic ports (LAN, WAN, etc.), and uses redundant upstream routers in addition to redundant switches.

For more information about Full Mesh deployment, see About Full Mesh Deployments and the Active/Active Clustering Full Mesh Deployment Technote, available on https://support.sonicwall.com/.

About Failover

There are two types of failover that can occur when Active/Active Clustering is enabled:

High Availability failover – Within an HA pair, the secondary unit takes over for the Primary. If Stateful HA is enabled for the pair, the failover occurs without interruption to network connections.
Active/Active failover – If all the units in the owner node for a Virtual Group encounter a fault condition, then the standby node for the Virtual Group takes over the Virtual Group ownership. Active/Active failover transfers ownership of a Virtual Group from one Cluster Node to another. The Cluster Node that becomes the Virtual Group owner also becomes the owner of all the virtual IP addresses associated with the Virtual Group and starts using the corresponding virtual MAC addresses.

Active/Active failover is stateless, meaning that network connections are reset and VPN tunnels must be renegotiated. Layer 2 broadcasts inform the network devices of the change in topology as the Cluster Node which is the new owner of a Virtual Group generates ARP requests with the virtual MACs for the newly owned virtual IP addresses. This greatly simplifies the failover process as only the connected switches need to update their learning tables. All other network devices continue to use the same virtual MAC addresses and do not need to update their ARP tables, because the mapping between the virtual IP addresses and virtual MAC addresses is not broken.

When both High Availability failover and Active/Active failover are possible, HA failover is given precedence over Active/Active failover for the following reasons:

HA failover can be stateful, whereas Active/Active failover is stateless.
The standby firewall in an HA pair is lightly loaded and has resources available for taking over the necessary processing, although it may already be handling DPI traffic if Active/Active DPI is enabled. The alternative Cluster Node might already be processing traffic comparable in amount to the failed unit, and could become overloaded after failover.

Active/Active failover always operates in Active/Active preempt mode. Preempt mode means that, after failover between two Cluster Nodes, the original owner node for the Virtual Group will seize the active role from the standby node after the owner node has been restored to a verified operational state. The original owner will have a higher priority for a Virtual Group due to its higher ranking if all virtual IP interfaces are up and the link weight is the same between the two Cluster Nodes.

* 
NOTE: High Availability preempt mode is not available if Active/Active Clustering is enabled.

In addition to the two types of failover, the following feature provides protection against a single point of failure:

Port Redundancy – Although technically not a failover, a redundant port provides backup by handling all the traffic if its partner has a fault. Port redundancy is available only when Active/Active Clustering is enabled.

About Active/Active DPI

Active/Active Clustering can be enabled with or without enabling Active/Active DPI, just as Active/Active DPI can be enabled with or without enabling Active/Active Clustering. For increased performance in an Active/Active cluster, enabling Active/Active DPI is recommended, as it uses the standby firewall in the HA pair for Deep Packet Inspection (DPI) processing.

To use the Active/Active DPI feature, you must configure an additional interface as the Active/Active DPI Interface. If you choose to make X5 the Active/Active DPI Interface, you must physically connect X5 on the active unit to X5 on the standby unit in the HA pair. Certain packet flows on the active unit are selected and offloaded to the standby unit on the Active/Active DPI Interface. DPI is performed on the standby unit and then the results are returned to the active unit over the same interface. The remaining processing is performed on the active unit.

For additional redundancy, you can connect and configure a second Active/Active DPI Interface on the HA pair. The redundant Active/Active DPI Interface is used for load sharing while offloading DPI traffic. When two Active/Active DPI Interfaces exist, both ports are used for receiving and returning the DPI traffic between the two firewalls on a packet by packet basis (not a session basis), in a round-robin manner.

After enabling Stateful Synchronization on the appliances in the HA pair and connecting and configuring the Active/Active DPI Interface(s), you can enable Active/Active DPI on the High Availability > Settings page.

About High Availability Monitoring

When Active/Active Clustering is enabled, HA monitoring configuration is supported for the HA pair in each Cluster Node. The HA monitoring features are consistent with previous versions. HA monitoring can be configured for both physical/link monitoring and logical/probe monitoring. After logging into the Master Node, monitoring configuration needs to be added on a per Node basis from the High Availability > Monitoring page.

* 
NOTE: The High Availability > Monitoring page applies only to the HA pair that you are logged into, not to the entire cluster.

Physical interface monitoring enables link detection for the monitored interfaces. The link is sensed at the physical layer to determine link viability.

When physical interface monitoring is enabled, with or without logical monitoring enabled, HA failover takes precedence over Active/Active failover. If a link fails or a port is disconnected on the active unit, the standby unit in the HA pair will become active.

* 
NOTE: For interfaces with configured virtual IP addresses, Active/Active physical monitoring is implicit and is used to calculate the Virtual Group Link Weight. Physical monitoring cannot be disabled for these interfaces. This is different from HA monitoring.

Logical monitoring involves configuring the SonicWall to monitor a reliable device on one or more of the connected networks. Failure to periodically communicate with the device by the active unit in the HA pair will trigger a failover to the standby unit. If neither unit in the HA pair can connect to the device, the problem is assumed to be with the device and no failover will occur.

If both physical monitoring and logical monitoring are disabled, Active/Active failover will occur on link failure or port disconnect.

The Primary and Secondary IP addresses configured on the High Availability > Monitoring page can be configured on LAN or WAN interfaces, and are used for multiple purposes:

As independent management addresses for each unit, regardless of the Active or Standby status of the unit (supported on all physical interfaces)
To allow synchronization of licenses between the standby unit and the SonicWall licensing server
As the source IP addresses for the probe pings sent out during logical monitoring

Configuring monitoring IP addresses for both units in the HA pair allows you to log in to each unit independently for management purposes. Note that non-management traffic is ignored if it is sent to one of the monitoring IP addresses. The Primary and Secondary SonicWall security appliance’s unique LAN IP addresses cannot act as an active gateway; all systems connected to the internal LAN will need to use a virtual LAN IP address as their gateway.

* 
NOTE: When HA Monitoring/Management IP addresses are configured only on WAN interfaces, they need to be configured on all the WAN interfaces for which a Virtual IP address has been configured.

The management IP address of the Secondary unit is used to allow license synchronization with the SonicWall licensing server, which handles licensing on a per-appliance basis (not per-HA pair). Even if the standby unit was already registered on MySonicWall before creating the HA association, you must use the link on the System > Licenses page to connect to the SonicWall server while accessing the Secondary appliance through its management IP address. This allows synchronization of licenses (such as the Active/Active Clustering or the Stateful HA license) between the standby unit and the SonicWall licensing server.

When using logical monitoring, the HA pair will ping the specified Logical Probe IP address target from the Primary as well as from the Secondary SonicWall. The IP address set in the Primary IP Address or Secondary IP Address field is used as the source IP address for the ping. If both units can successfully ping the target, no failover occurs. If both cannot successfully ping the target, no failover occurs, as the SonicWalls will assume that the problem is with the target, and not the SonicWalls. But, if one SonicWall can ping the target but the other SonicWall cannot, the HA pair will failover to the SonicWall that can ping the target.

The configuration tasks on the High Availability > Monitoring page are performed on the Primary unit and then are automatically synchronized to the Secondary unit.

About Full Mesh Deployments

Active/Active Clustering Full Mesh configuration is an enhancement to the Active/Active Clustering configuration option and provides the highest level of availability possible with high performance. Full Mesh deployments provide a very high level of availability for the network, because all devices have one or more redundant partners, including routers, switches, and security appliances. Every device is wired twice to the connected devices, so that no single point of failure exists in the entire network. For example, every SonicWall firewall uses redundant ports to connect twice to each networking device.

* 
NOTE: Full Mesh deployments require that Port Redundancy is enabled and implemented.

For more information about Full Mesh deployments, see the Active/Active Clustering Full Mesh Deployment Technote, available on https://support.sonicwall.com/.

Topics:
Example of a 4-unit Full Mesh Deployment

Four-Unit Full Mesh Deployment shows a 4-unit Full Mesh deployment.

Four-Unit Full Mesh Deployment

Example of a 2-unit Full Mesh Deployment

You can also configure a Full Mesh deployment using only two firewalls, one per Cluster Node, as shown in Two-Unit Full Mesh Deployment.

Two-Unit Full Mesh Deployment

Platform and Feature Support Information

Topics:

Supported SonicWall Platforms

Active/Active Clustering is available in the SonicOS 5.9 release on the following SonicWall security appliances:

SonicWall NSA E8500
SonicWall NSA E8510
SonicWall NSA E7500
SonicWall NSA E6500
SonicWall NSA E5500

Feature Caveats

When Active/Active Clustering is enabled, only static IP addresses can be used on the WAN.

The following features are not supported when Active/Active Clustering is enabled:

DHCP Server
L3 Transparent Mode
L2 Bridging / L2 Transparent Mode
Dynamic DNS

The following features are only supported on Virtual Group 1:

SonicWall GVC
SonicOS SSL VPN
IP Helper

Backward Compatibility

The Active/Active Clustering feature is not backward compatible. When upgrading to SonicOS 5.9, it is highly recommended that you disable High Availability before exporting the preferences from an HA pair running a previous version of SonicOS.

SonicPoint Compatibility

There are two points to consider when using SonicWall SonicPoints together with Active/Active Clustering:

SonicPoints only communicate with the Master node for downloading firmware and other aspects of operation.
SonicPoints need access to an independent DCHP server. SonicPoints require a DHCP server to provide IP addresses to wireless clients, but the embedded SonicOS DHCP server is disabled automatically when Active/Active Clustering is enabled.

WAN Load Balancing Compatibility

When WAN Load Balancing (WLB) is enabled in an Active/Active Cluster, the same WLB interface configuration is used for all nodes in the cluster.

A WAN interface failure can trigger either a WLB failover , an HA pair failover, or an Active/Active failover to another Cluster Node, depending on the following:

WAN goes down logically due to WLB probe failure – WLB failover
Physical WAN goes down while Physical Monitoring is enabled – HA pair failover
Physical WAN goes down while Physical Monitoring is not enabled – Active/Active failover

Routing Topology and Protocol Compatibility

This section describes the current limitations and special requirements for Active/Active Clustering configurations with regard to routing topology and routing protocols.

Topics:
Layer-2 Bridge Support

Layer-2 Bridged interfaces are not supported in a cluster configuration.

Routing Protocol Support
Topics:
OSPF

OSPF is supported with Active/Active Clustering. When enabled, OSPF runs on the OSPF-enabled interfaces of each active Cluster Node. From a routing perspective, all Cluster Nodes appear as parallel routers, each with the virtual IP address of the Cluster Node's interface. In general, any network advertised by one node will be advertised by all other nodes.

The OSPF router-ID of each Cluster Node must be unique and will be derived from the router-ID configured on the Master node as follows:

If the user enters 0 or 0.0.0.0 for the router-ID in the OSPF configuration, each node’s router-ID will be assigned the node’s X0 virtual IP address.
If the user enters any value other than 0 or 0.0.0.0 for the router-ID, each node will be assigned a router-ID with consecutive values incremented by one for each node. For example, in a 4-node cluster, if the router-ID 10.0.0.1 was configured on the Master node, the router-ID’s assigned would be as follows:
Node 1: 10.0.0.1
Node 2: 10.0.0.2
Node 3: 10.0.0.3
Node 4: 10.0.0.4
RIP

RIP is supported, and like OSPF, will run on the RIP-enabled interfaces of each Cluster Node. From a routing perspective, all Cluster Nodes will appear as parallel routers with the virtual IP address of the Cluster Node’s interface. In general, any network advertised by one node will be advertised by all other nodes.

BGP

BGP is supported in clusters, and will also appear as parallel BGP routers using the virtual IP address of the Cluster Node’s interface. As with OSPF and RIP, configuration changes made on the Master node will be applied to all other Cluster Nodes. In the case of BGP, where configuration may only be applied through the CLI, the configuration is distributed when the running configuration is saved with the write file CLI command.

Asymmetric Routing Issues In Cluster Configurations

Any network appliance that performs deep packet inspection or stateful firewall activity must “see” all packets associated with a packet flow. This is in contrast to traditional IP routing in which each packet in a flow may technically be forwarded along a different path as long as it arrives at it’s intended destination – the intervening routers do not have to see every packet. Today’s routers do attempt to forward packets with a consistent next-hop for each packet flow, but this applies only to packets forwarded in one direction. Routers make no attempt to direct return traffic to the originating router. This IP routing behavior presents problems for a firewall cluster because the set of Cluster Nodes all provide a path to the same networks. Routers forwarding packets to networks through the cluster may choose any of the Cluster Nodes as the next-hop. The result is asymmetric routing, in which the flow of packets in one direction go through a node different than that used for the return path. This will cause traffic to be dropped by one or both Cluster Nodes since neither is “seeing” all of the traffic from the flow.

There are two ways to avoid asymmetric routing paths:

1
Engineer all networks and routers connected to the cluster such that packet forwarding will always result in symmetric paths in respect to the virtual IP addresses used in the cluster.
2
Create a full mesh configuration of NAT rules in the cluster so every interface-pair has a NAT rule which replaces the source IP address in the packet with the virtual IP of the egress interface. These rules should be the same as the default rules created between trusted and non-trusted zoned interfaces. When the full mesh NAT rules are in place, the forward and reverse paths of flows transiting the cluster will always flow through the same Cluster Node (or the current owner of the Cluster Node’s primary virtual IP addresses).

Active/Active Clustering Prerequisites

This section describes the requirements for registering your SonicWall appliance and licensing the SonicWall High Availability features.

Topics:

Registering and Licensing Requirements

Topics:
Registering and Associating Appliances on MySonicWall

To use Active/Active Clustering, you must register all SonicWall appliances in the cluster on MySonicWall. The two appliances in each HA pair must also be associated as HA Primary and HA Secondary on MySonicWall. That is, associate the two appliances in the HA pair for Cluster Node 1, then associate the appliances in the HA pair for Cluster Node 2, and so on for any other Cluster Nodes.

* 
NOTE: The Secondary appliance of the HA pair is referred to as the HA Secondary unit on MySonicWall.

After the appliances are associated as an HA pair, they can share licenses. In addition to High Availability licenses, this includes the SonicOS Enhanced license, the Support subscription, and the security services licenses. The only licenses that are not shareable are for consulting services, such as the SonicWall GMS Preventive Maintenance Service.

It is not required that the Primary and Secondary appliances have the same security services enabled. The security services settings will be automatically updated as part of the initial synchronization of settings. License synchronization is used so that the Secondary appliance can maintain the same level of network protection provided before the failover.

MySonicWall provides several methods of associating the two appliances. You can start by registering a new appliance, and then choosing an already-registered unit to associate it with. Or, you can associate two units that are both already registered. You can also start the process by selecting a registered unit and adding a new appliance with which to associate it.

* 
NOTE: Even if you first register your appliances on MySonicWall, you must individually register both the Primary and the Secondary appliances from the SonicOS management interface while logged into the individual management IP address of each appliance. This allows the Secondary unit to synchronize with the SonicWall license server and share licenses with the associated Primary appliance. When Internet access is restricted, you can manually apply the shared licenses to both appliances.

For information about configuring and using the individual management IP address of each appliance, see About High Availability Monitoring and Configuring High Availability Monitoring.

Licensing High Availability Features
* 
NOTE: For generic HA licensing requirements, see Licensing.

Active/Active Clustering, Stateful Synchronization, and Active/Active DPI licenses are included on registered SonicWall NSA E-Class appliances. Because Active/Active Clustering is supported only on E-Class appliances, you do not need to purchase any additional licenses to use these High Availability features in SonicOS 5.9.

* 
NOTE: Active/Active Clustering and Stateful Synchronization licenses must be activated on each appliance, either by registering the unit on MySonicWall from the SonicOS management interface, or by applying the license keyset to each unit if Internet access is not available.

You can view system licenses on the System > Licenses page of the management interface. This page also provides a way to log into MySonicWall.

When the SonicWall security appliances in the Active/Active cluster have Internet access, each appliance in the cluster must be individually registered from the SonicOS management interface while you are logged on the individual management IP address of each appliance. This allows the Secondary units to synchronize with the SonicWall licensing server and share licenses with the associated Primary appliances in each HA pair.

There is also a way to synchronize licenses for an HA pair whose appliances do not have Internet access. When live communication with SonicWall's licensing server is not permitted due to network policy, you can use license keysets to manually apply security services licenses to your appliances. When you register a SonicWall security appliance on MySonicWall, a license keyset is generated for the appliance. If you add a new security service license, the keyset is updated. However, until you apply the licenses to the appliance, it cannot perform the licensed services.

* 
NOTE: In a High Availability deployment without Internet connectivity, you must apply the license keyset to both of the appliances in the HA pair.

To apply licenses to an appliance, you can use one of the procedures found in Activating, Upgrading, or Renewing Services.

Active/Active Clustering Prerequisites

* 
NOTE: In addition to the requirements described in this section, ensure that you have completed the prerequisites described in Active/Standby and Active/Active DPI Prerequisites.

For Active/Active Clustering, additional physical connections are required:

Active/Active Cluster Link—Each Active/Active cluster link must be a 1GB interface

Active/Active Clustering configuration can include configuring Virtual Group IDs and redundant ports. Procedures are provided in this section for both of these tasks within High Availability > Settings.

Topics:
Connecting the HA Ports for Active/Active Clustering

For Active/Active Clustering, you must physically connect the designated HA ports of all units in the Active/Active cluster to the same Layer 2 network.

SonicWall recommends connecting all designated HA ports to the same Layer 2 switch. You can use a dedicated switch or simply use some ports on an existing switch in your internal network. All of these switch ports must be configured to allow Layer 2 traffic to flow freely amongst them.

For a two-unit Active/Active cluster deployment, where the two Cluster Nodes each have only a single appliance, you can connect the HA ports directly to each other using a cross-over cable. No switch is necessary in this case.

The SonicWall Virtual Router Redundancy Protocol (SVRRP) uses this HA port connection to send Cluster Node management and monitoring state messages. SVRRP management messages are initiated on the Master Node, and monitoring information is communicated from every appliance in the cluster.

The HA port connection is also used to synchronize configuration from the Master Node to the other Cluster Nodes in the deployment. This includes firmware or signature upgrades, policies for VPN and NAT, and other configuration.

Connecting Redundant Port Interfaces

You can assign an unused physical interface as a redundant port to a configured physical interface called the “primary interface”. On each Cluster Node, each primary and redundant port pair must be physically connected to the same switch, or preferably, to redundant switches in the network.

* 
NOTE: Because all Cluster Nodes share the same configuration, each node must have the same redundant ports configured and connected to the same switch(es).

To use Active/Active Clustering, you must register all SonicWall appliances in the cluster on MySonicWall. The two appliances in each HA pair must also be associated as HA Primary and HA Secondary on MySonicWall. That is, associate the two appliances in the HA pair for Cluster Node 1, then associate the appliances in the HA pair for Cluster Node 2, and so on for any other Cluster Nodes.

Configuration Task List

This section provides a high-level task list for getting the Active/Active Clustering and other High Availability features up and running.

Perform the following tasks:

1
Physically connect the designated HA ports of all units in the Active/Active cluster to the same Layer 2 network.
2
Physically connect an additional interface between the two appliances in each HA pair if you plan to enable Active/Active DPI. The interface must be the same number on both appliances. For example, connect X4 on the Primary unit to X4 on the Secondary unit.
3
Optionally, for port redundancy for Active/Active DPI ports, physically connect a second interface between the two appliances in each HA pair. This interface will take over transferring data between the two units during Active/Active DPI processing if the first Active/Active DPI Interface has a fault.
4
Physically connect the LAN and WAN ports of all units to the appropriate switches.
5
Optionally, if you plan to use redundant ports for the LAN/WAN ports, connect the redundant ports to the appropriate switches.
6
Power down all the units except the unit that is to be designated as the Primary unit in Cluster Node 1.
7
Login to the Primary unit in Cluster Node 1, leaving other units down.
8
On the Network > DHCP Server page, disable the DHCP server and delete all DHCP server lease scopes. See Disabling the SonicOS DHCP Server.
9
Configure IP addresses for the desired interfaces on the Network > Interfaces page.
10
Select Active/Active Clustering on the High Availability > Settings page.
11
Enter the serial numbers of other units in the Active/Active cluster.
12
Enter the Cluster Node owner/standby ranking for each Virtual Group.
13
Click Apply.
14
Configure Virtual Group IP addresses on the Network > Interfaces page.
* 
NOTE: Default NAT policies are created automatically, so there is no need to configure NAT policies for Virtual Groups in the Network > NAT Policies page
15
Configure settings in the High Availability > Advanced page.
16
Start up the other units in the Active/Active cluster.
17
Configure per-unit IP addresses in the High Availability > Monitoring page.
* 
NOTE: Per-unit IP addresses (HA monitoring IP addresses) are required for all the units in the cluster either on Primary LAN or on Primary WAN Interfaces.
18
Login to each unit using the per-unit IP address, and click Register and synchronize licenses with the MySonicWall Licensing server.
19
Enable Stateful Synchronization.
20
Enable Active/Active DPI and configure the appropriate interface as the Active/Active DPI Interface.
21
If a second interface is physically connected, configure it as the Active/Active DPI Interface 2 for Active/Active DPI.

Physically Connecting Your Active/Active Cluster Appliances

High Availability requires additional physical connections among the affected SonicWall appliances. This section describes the physical connections needed for Active/Active Clustering and Active/Active DPI.

* 
NOTE: For complete procedures for connecting your appliances see the Getting Started Guide for your appliance and Physically Connecting Your Appliances.
Topics:

Connecting the HA Ports for Active/Active Clustering

For Active/Active Clustering, you must physically connect the designated HA ports of all units in the Active/Active cluster to the same Layer 2 network. The SonicWall E-Class NSA appliance have a dedicated HA port which should be used. On the NSA 3500/4500/5000, use interface X5.

SonicWall recommends connecting all designated HA ports to the same Layer 2 switch. You can use a dedicated switch or simply use some ports on an existing switch in your internal network. All of these switch ports must be configured to allow Layer 2 traffic to flow freely amongst them.

In the case of a two-unit Active/Active cluster deployment, where the two Cluster Nodes each have only a single appliance, you can connect the HA ports directly to each other using a cross-over cable. No switch is necessary in this case.

The SonicWall Virtual Router Redundancy Protocol (SVRRP) uses this HA port connection to send Cluster Node management and monitoring state messages. SVRRP management messages are initiated on the Master Node, and monitoring information is communicated from every appliance in the cluster.

The HA port connection is also used to synchronize configuration from the Master Node to the other Cluster Nodes in the deployment. This includes firmware or signature upgrades, policies for VPN and NAT, and other configuration.

Connecting the Active/Active DPI Interfaces for Active/Active DPI

For Active/Active DPI, you must physically connect at least one additional interface, called the Active/Active DPI Interface, between the two appliances in each HA pair, or Cluster Node. The connected interfaces must be the same number on both appliances, and must initially appear as unused, unassigned interfaces in the Network > Interfaces page. For example, you could connect X5 on the Primary unit to X5 on the Secondary if X5 is an unassigned interface. After enabling Active/Active DPI, the connected interface will have a Zone assignment of HA Data-Link.

Certain packet flows on the active unit are selected and offloaded to the standby unit on the Active/Active DPI Interface. DPI is performed on the standby unit and then the results are returned to the active unit over the same interface.

Optionally, for port redundancy with Active/Active DPI, you can physically connect a second Active/Active DPI Interface between the two appliances in each HA pair. This interface will take over transferring data between the two units during Active/Active DPI processing if the first Active/Active DPI Interface has a fault.

To connect the Active/Active DPI Interfaces for Active/Active DPI:
1
Decide which interface to use for the additional connection between the appliances in the HA pair. The same interface must be selected on each appliance.
2
In the SonicOS management interface:
a
Navigate to the Network > Interfaces page.
b
Ensure that the Zone is Unassigned for the intended Active/Active DPI Interface.
3
Using a standard Ethernet cable, connect the two interfaces directly to each other.
4
Optionally, for port redundancy with Active/Active DPI, physically connect a second Active/Active DPI Interface between the two appliances in each HA pair.

Connecting the LAN and WAN Interfaces in a High Availability Deployment

In any High Availability deployment, you must physically connect the LAN and WAN ports of all units to the appropriate switches.

A WAN connection to the Internet is useful for registering your appliances on MySonicWall and for synchronizing licensing information. Unless live communication with SonicWall's licensing server is not permitted due to network policy, the WAN (X1) interface should be connected before registration and licensing are performed.

Connecting Redundant Port Interfaces

Redundant ports can be configured when Active/Active Clustering is enabled. You can assign an unused physical interface as a redundant port to a configured physical interface called the “primary interface”. On each Cluster Node, each primary and redundant port pair must be physically connected to the same switch, or preferably, to redundant switches in the network.

* 
NOTE: Because all Cluster Nodes share the same configuration, each node must have the same redundant ports configured and connected to the same switch(es).

For examples of clustering deployment, see Active/Active Clustering – Four-Unit Deployment and Active/Active Clustering – Two-Unit Deployment.

Viewing High Availability Active/Active Cluster Status

The High Availability > Status page provides status for the entire Active/Active cluster and for each Cluster Node in the deployment. The status for the Active/Active cluster node is displayed in the upper table, and status for High Availability is displayed in the lower table.

Configuring Active/Active Clustering and High Availability

Active/Active Clustering configuration can include configuring Virtual Group IDs and redundant ports. Procedures are provided in this section for both of these tasks within the Configuring Network DHCP and Interface Settings section. This section also includes the procedure for disabling the DHCP server and deleting existing lease scopes.

There are four High Availability pages in the SonicOS management interface. Of these, two have configurable settings that pertain to Active/Active Clustering, one displays status for both the cluster and the HA pair to which you are logged in, and one pertains only to configuration for the local HA pair. The latter is the High Availability > Monitoring page. This section describes the configuration options for all High Availability settings, whether they pertain to Active/Active Clustering or only to the HA pair.

Topics:

Configuring Network DHCP and Interface Settings

When Active/Active Clustering is enabled, the SonicOS internal DHCP server is turned off and cannot be enabled. Networks needing a DHCP server can use an external DHCP server. The SonicOS DHCP server should be disabled in the management interface before enabling Active/Active Clustering, and all DHCP server lease scopes deleted.

On the Network > Interfaces page, you can configure additional virtual IP addresses for interfaces in a Virtual Group and redundant ports for interfaces.

Topics:
Disabling the SonicOS DHCP Server
To disable the SonicOS DHCP server and delete all DHCP server lease scopes:
1
Login to the Primary unit of the Cluster Node and navigate to the Network > DHCP Server page.
2
Clear the Enable DHCP Server check box.
3
Under DHCP Server Lease Scopes, select the check box at the top left corner of the table heading to select all lease scopes in the table.

4
Click the Delete All button.
5
Click OK in the confirmation dialog.
6
Click Accept at the top of the Network > DHCP Server page.
Configuring Virtual IP Addresses

When Active/Active Clustering is enabled for the first time, the configured IP addresses for the interfaces on that firewall are automatically converted to virtual IP addresses for Virtual Group 1. Thus, Virtual Group 1 will include virtual IP addresses for X0, X1, and any other interfaces which are configured and assigned to a zone.

Active/Active Clustering requires additional configuration of virtual IP addresses for additional Virtual Groups. You can assign multiple virtual IP addresses to each interface, one per Virtual Group. Each additional virtual IP address is associated with one of the other Virtual Groups in the cluster. Each interface can have up to a maximum of four virtual IP addresses. VLAN interfaces can also have up to four virtual IP addresses.

* 
NOTE: A packet cannot be forwarded on an interface if a virtual IP address is not configured on it for the Virtual Group handling that traffic flow.
To configure a virtual IP address on an interface:
1
Login to the Primary unit of the Cluster Node.
2
Navigate to the Network > Interfaces page.
3
In the Interface Settings table, click the Configure icon for the interface you want to configure.
4
In the Edit Interface dialog, type the virtual IP address into the IP Address (Virtual Group X) field, where X is the virtual group number.

* 
NOTE: The new virtual IP address must be in the same subnet as any existing virtual IP address for that interface.
5
Click OK. The configured virtual IP address appears in the Interface Settings table.

Configuring Redundant Ports

Redundant ports can be configured when Active/Active Clustering is enabled. You can assign an unused physical interface as a redundant port to a configured physical interface called the “primary interface”. If there is a physical link failure on the primary interface, the redundant interface can continue processing traffic without any interruption. One advantage of this feature is that in case of a physical link failure, there is no need to do a device failover.

You can configure a redundant port on the Advanced tab of the Edit Interface dialog. The Redundant Port field is only available when Active/Active Clustering is enabled.

* 
NOTE: Because all Cluster Nodes share the same configuration, each node must have the same redundant ports configured and connected to the same switch(es).

For information about physically connecting redundant ports and redundant switches, see the Active/Active Clustering Full Mesh Deployment Technote.

To configure a redundant port for an interface:
1
Login to the Primary unit of the Cluster Node.
2
Navigate to the Network > Interfaces page.
3
In the Interface Settings table, click the Configure icon for the primary interface for which you want to create a redundant port. For example, click the configure icon for X2.

4
In the Edit Interface dialog, click the Advanced tab.

5
In the Redundant Port field, select the redundant port from the drop-down menu. Only unused interfaces are available for selection. For example, select X4 for the redundant port.
6
Click OK.

The selected interface will no longer appear in the Interface Settings table. After configuration, it appears only in the Redundant Port field in the Edit Interface dialog of the primary port.

* 
NOTE: The primary and redundant ports must be physically connected to the same switch, or preferably, to redundant switches in the network.
7
On each Cluster Node, replicate the redundant physical connections using the same interface numbers for primary and redundant ports. All Cluster Nodes share the same configuration as the Master node.

Configuring High Availability Settings

* 
NOTE: For a complete description of configuring HA settings, see Configuring Active/Active DPI High Availability Settings.
To configure your SonicWall deployment to use Active/Active Clustering:
1
Login to the Primary unit of the Master Cluster Node.
2
Navigate to the High Availability > Settings page.
3
Under High Availability Settings, select Active/Active DPI Clustering from the drop-down menu. A new tab, HA Interfaces, appears and the Enable Stateful Synchronization option is dimmed, but enabled automatically for Active/Active DPI.

4
For Stateful Synchronization in the master Cluster Node, select the Enable Stateful Synchronization check box if it is not yet enabled.
5
Under the HA Interfaces tab, from the drop-down menus, select the interfaces you want. These interface are used for transferring data between the two units during Active/Active DPI processing. Only unassigned, available interfaces appear in the drop-down menu.

6
Click Apply.

On the Network > Interfaces page, Virtual Group 1 is displayed with its corresponding virtual IP addresses. The Active/Active DPI Interface(s) are shown as members of the HA Data-Link zone.

Configuring High Availability Advanced Settings

* 
NOTE: For a complete description of configuring HA advanced settings, see Configuring High Availability > Advanced Settings.

The Heartbeat Interval and Failover Trigger Level settings on the High Availability > Advanced page apply to both the SVRRP heartbeats (Active/Active Clustering heartbeat) and HA heartbeats.

Other settings on High Availability > Advanced page apply only to the HA pairs within the Cluster Nodes.

To configure the settings on the High Availability > Advanced page:
1
Login as an administrator to the SonicOS management interface on the Master Node, that is, on the Virtual Group1 IP address (on X0 or another interface with HTTP management enabled).
2
Navigate to High Availability > Advanced.

* 
NOTE: The minimum settings shown for the options are minimum recommended values. Lower values may cause unnecessary failovers, especially when theSonicWall is under a heavy load. Use higher values if your SonicWall handles a lot of network traffic.
3
Follow the procedure described in Configuring High Availability > Advanced Settings.
4
When finished with all High Availability configuration, click Apply. All settings are synchronized to the other units in the cluster.

Configuring High Availability Monitoring

The configuration tasks on the High Availability > Monitoring page are performed on the Primary unit and then are automatically synchronized to the Secondary.

To set the independent LAN management IP addresses and configure physical and/or logical interface monitoring:
1
Login as an administrator to the SonicOS management interface on the Master Node.
2
Navigate to High Availability > Monitoring.
3
Follow the procedure for configuring High Availability Monitoring settings in Configuring the High Availability > Monitoring Page Settings.
4
To configure monitoring on any of the other interfaces, repeat Step 3 for each interface.
5
When finished with all High Availability monitoring configuration for the selected Cluster Node, click Apply.
6
Then select a different Cluster Node and repeat the configuration steps.
7
Click Apply.

Configuring Virtual Group Association in VPN Policies

VPN policy configuration requires association with a Virtual Group when running in Active/Active Clustering mode. Follow the procedures described in Configuring GroupVPN Policies.

Virtual Group address objects are available from the Choose local network from list drop-down menu. These Virtual Group address objects are created by SonicOS when virtual IP addresses are added and are deleted when the virtual IP is deleted.

When creating a VPN Policy for a remote network, Virtual Group address objects may also be available.

Configuring Virtual Group Association in NAT Policies

When running in Active/Active Clustering mode, NAT policy configuration includes Virtual Group settings. Default NAT policies are created by SonicOS when virtual IP addresses are added and are deleted when the virtual IP is deleted. You can specify a Virtual Group or select Any when creating custom NAT policies. The procedures for creating NAT polices are described in Creating NAT Policies.

Verifying Active/Active Clustering Configuration

This section describes several methods of verifying the correct configuration of Active/Active Clustering and Active/Active DPI.

Topics:
Comparing CPU Activity on Appliances in a Cluster

On the active firewall of the Master node, the System > Diagnostics page with Multi-Core Monitor selected shows the activity of all appliances in the Active/Active cluster. The following figure displays the Multi-Core Monitor on an Active/Active cluster with Active/Active DPI enabled. This configuration utilizes all units in the cluster for the highest possible performance.

When Active/Active DPI is enabled on a Stateful HA pair, you can observe a change in CPU utilization on appliances in the HA pair. CPU activity goes down on the active unit, and goes up on the standby unit.

When viewing the Multi-Core Monitor on an active unit in the cluster, all firewalls in the cluster are displayed. However, if you log into the individual IP address of an standby unit in the cluster, the Multi-Core Monitor page only displays the core usage for the two firewalls in that particular HA pair.

* 
NOTE: To see the core usage for all firewalls in the cluster, SonicWall recommends viewing the Multi-Core Monitor page on the active unit of the Master node.
Verifying Settings in the High Availability > Status Page

The High Availability > Status page provides status for the entire Active/Active cluster and for each Cluster Node in the deployment. For complete information about the High Availability > Status page, see High Availability > Status.

The Active/Active Clustering node status is displayed at the top of the page, and shows values for the following settings:

Node Status – Active or Standby for each node in the cluster
Primary A/A Licensed – Yes or No for each node in the cluster
Secondary A/A Licensed – Yes or No for each node in the cluster
Virtual Groups Owned – Displays the Virtual Group number owned by each node in the cluster. You can check these values to determine the owner status after a failover.

The Active/Active Clustering Node Status table is shown on the High Availability > Status page.

Displaying High Availability Status

High Availability > Status

On the High Availability > Status page, you can check the status of the High Availability feature and the appliances running it.

Topics:

Viewing Active/Standby High Availability Status

The High Availability Status table on the High Availability > Status page displays the current status of the HA Pair. If the Primary SonicWall is Active, the first line in the table indicates that the Primary SonicWall is currently Active.

It is also possible to check the status of the Secondary SonicWall by logging into the unique LAN IP address of the Secondary SonicWall. If the Primary SonicWall is operating normally, the status indicates that the Secondary SonicWall is currently Standby. If the Secondary has taken over for the Primary, the status table indicates that the Secondary is currently Active.

If the Primary SonicWall fails, you can access the management interface of the Secondary SonicWall at the Primary SonicWall virtual LAN IP address or at the Secondary SonicWall LAN IP address. When the Primary SonicWall restarts after a failure, it is accessible using the unique IP address created on the High Availability > Monitoring page. If preempt mode is enabled, the Primary SonicWall becomes the Active firewall and the Secondary firewall returns to Standby status.

There are three tables on the High Availability > Status page:

High Availability Status Table

Status – The values in this field are prepended with Primary or Secondary, depending on which appliance the table is being viewed. The possible values are:
Active – This appliance is in the ACTIVE state.
Standby – This appliance is in the STANDBY state.
Disabled – High Availability has not been enabled in the management interface of this appliance.
Not in a steady state – HA is enabled and the appliance is neither in the ACTIVE nor the STANDBY state.
Primary State - The current state of the Primary appliance as a member of an HA Pair. The Primary State field is displayed on both the Primary and the Secondary appliances.
ACTIVE – The Primary unit is handling all the network traffic except management/monitoring/licensing traffic destined to the STANDBY unit.
STANDBY – The Primary appliance is passive and is ready to take over on a failover.
ELECTION – The Primary and Secondary units are negotiating which should be the ACTIVE unit.
SYNC – The Primary unit is synchronizing settings or firmware to the Secondary.
ERROR – The Primary unit has reached an error condition.
REBOOT – The Primary unit is rebooting.
NONE – When viewed on the Primary unit, NONE indicates that HA is not enabled on the Primary. When viewed on the Secondary unit, NONE indicates that the Secondary unit is not receiving heartbeats from the Primary unit.
Secondary State – The current state of the Secondary appliance as a member of an HA Pair. The Secondary State field is displayed on both the Primary and the Secondary appliances.
ACTIVE – The Secondary unit is handling all the network traffic except management/monitoring/licensing traffic destined to the STANDBY unit.
STANDBY – The Primary appliance is passive and is ready to take over on a failover.
ELECTION – The Secondary and Primary units are negotiating which should be the ACTIVE unit.
SYNC – The Secondary unit is synchronizing settings or firmware to the Primary.
ERROR – The Secondary unit has reached an error condition.
REBOOT – The Secondary unit is rebooting.
NONE – When viewed on the Secondary unit, NONE indicates that HA is not enabled on the Secondary. When viewed on the Primary unit, NONE indicates that the Primary unit is not receiving heartbeats from the Secondary unit.
Active Up Time – Indicates how long the current Active firewall has been Active since it last became Active:
Days Days Hours:Minutes:Seconds (for example, 31 Days 21:12:57)
High Availability Disabled – This line only displays when High Availability is disabled.

If failure of the Primary SonicWall occurs, the Secondary SonicWall assumes the Primary SonicWall LAN and WAN IP addresses. There are three main methods to check the status of the High Availability Pair:

High Availability > Status, High Availability Status table
Node Status – Indicates if Active/Active Clustering is enabled or is not enabled.
Found Peer – Indicates Yes if the Primary appliance has detected the Secondary appliance, and No if there is no HA link or if the Secondary is rebooting.
Settings Synchronized – Indicates if the settings are synchronized between the two appliances. This includes all settings that are part of the system preferences, for example, NAT policies, routes, user accounts. Possible values are Yes or No.
Stateful HA Synchronized – Indicates if the Standby appliance is synchronized with the initial state of the Active appliance (TCP sessions, VPN tunnels) when they discover each other. The possible values are Yes and No. No could mean that the stateful synchronization process for the initial state is in progress.
* 
NOTE: No is also displayed if Stateful HA is not enabled or licensed on either of the units.

High Availability Configuration Table

The High Availability Configuration table shows the configuration selected in the High Availability > Settings page.

HA Mode – Indicates the mode in which the appliance is running:
None
Active/Standby
Active/Active DPI
Active/Active Clustering
Active/Active DPI Clustering

One method to determine which SonicWall is Active is to check the HA Settings Status indicator on the High Availability > Settings page. If the Primary SonicWall is Active, the first line in the page indicates that the Primary SonicWall is currently Active.

It is also possible to check the status of the Secondary SonicWall by logging into the LAN IP address of the Secondary SonicWall. If the Primary SonicWall is operating normally, the status indicates that the Secondary SonicWall is currently Standby. If the Secondary has taken over for the Primary, the status indicates that the Secondary is currently Active.

HA Control Link – Indicates the port, speed, and duplex settings of the HA link, such as HA 1 Gbps Full Duplex, when two SonicWall NSA E-Class appliances are connected over their dedicated HA interfaces.

On a SonicWall NSA appliance that does not have a dedicated HA interface, this field displays the designated interface, such as X5, instead of HA. When the HA interfaces are not connected or the link is down, the field displays the status in the form X5 No Link. When High Availability is not enabled, the field displays Disabled.

Active/Active DPI Link
Active/Active DPI Link 2

High Availability Licenses Table

The High Availability Licenses table displays whether stateful HA and Active/Active services are licensed.

Primary Stateful HA Licensed – Indicates if the Primary appliance has a stateful HA license: Yes or No.
Secondary Stateful HA Licensed – Indicates if the Secondary appliance has a stateful HA license: Yes, No, or NA.
* 
NOTE: The Stateful HA license is shared with the Primary, but you must access mySonicWall.com while logged into the LAN management IP address of the Secondary unit to synchronize with the SonicWall licensing server.
Primary Active/Active Licensed – Indicates if Active/Active mode is licensed on the Primary appliance: Yes or No.

Viewing Active/Active High Availability Status

For information on High Availability status and verifying the configuration, see Verifying Active/Active Clustering Configuration

 

Configuring High Availability

High Availability > Settings

Topics:
* 
NOTE: For more information on High Availability, see What Is High Availability? and Active/Standby and Active/Active DPI Prerequisites. If your Active/Active Clustering environment will use VPN or NAT, see Configuring Virtual Group Association in VPN Policies or Configuring Virtual Group Association in NAT Policies after you have finished the Active/Active configuration.

Configuring Active/Standby High Availability Settings

The configuration tasks on the High Availability > Settings page are performed on the Primary unit and then are automatically synchronized to the Secondary.

To configure the settings on the High Availability > Settings page:
1
Navigate to High Availability > Settings.

2
On the General tab, the Mode drop-down menu specifies the High Availability Mode. Select Active/Standby to activate standard HA configuration and hardware failover functionality, with the option of enabling Stateful HA and Active/Active DPI. The default is None and all the options are dimmed.
* 
NOTE: License and signature updates will not work on Standby firewalls unless HA Monitoring IPs are set for either X0 or any one of the WAN interfaces.
3
To configure Stateful Synchronization (Stateful High Availability), available on SonicWall NSA series appliances, select the Enable Stateful Synchronization. This option is disabled by default.
* 
NOTE: The selected interface must be the same one that you physically connected as described in Physically Connecting Your Appliances.

By maintaining continuous synchronization between the primary and secondary appliances, Stateful HA enables the secondary appliance to take over in case of a failure with virtually no down time or loss of network connections.

When Stateful Synchronization is not enabled, the session state is not synchronized between the Primary and Secondary SonicWall security appliances. If a failover occurs, any session that had been active at the time of failover needs to be renegotiated.

When Stateful Synchronization is not enabled, it is not possible to enable the Active/Active DPI feature.

* 
NOTE: This option is not available for None and Active/Active DPI modes.

Stateful Synchronization recommended settings: 1000 milliseconds for Heartbeat Interval and 5 seconds for Probe Interval. These settings are minimum recommended values. Lower values may cause unnecessary failovers, especially when the SonicWall is under a heavy load. You can use higher values if your SonicWall handles a lot of network traffic.

4
Optionally, to back up the settings automatically when you upgrade the firmware version, select Generate/Overwrite Secondary Firmware and Settings When Upgrading Firmware. This option is disabled by default.
5
Optionally, to configure the High Availability Pair so that the Primary unit takes back the Primary role once it restarts after a failure, select Enable Preempt Mode. Preempt mode is recommended to be disabled when enabling Stateful Synchronization, because preempt mode can be over-aggressive about failing over to the Secondary appliance. This option is disabled by default.
6
To allow the Primary and Secondary appliances to share a single MAC address, select Enable Virtual MAC. This greatly simplifies the process of updating network ARP tables and caches when a failover occurs. Only the switch to which the two appliances are connected needs to be notified. All outside devices will continue to route to the single shared MAC address. This option is disabled by default.
7
Click the HA Devices tab to configure the Primary and Secondary appliance serial number.

* 
NOTE: License and signature updates will not work on Standby firewalls unless HA Monitoring IPs are set for either X0 or any one of the WAN interfaces.
8
Enter the serial number for the Secondary device in the Secondary Device Serial Number field.

The serial number for the Primary device is populated automatically and cannot be changed. For the Secondary unit, you can find the serial number on the back of the SonicWall security appliance or in the System > Status page.

9
Click Apply.

Configuring Active/Active DPI High Availability Settings

The configuration tasks on the High Availability > Settings page are performed on the Primary unit and then are automatically synchronized to the Secondary.

To configure Active/Active DPI on the High Availability > Settings page:
1
Navigate to High Availability > Settings.

2
On the General tab, the Mode drop-down menu specifies the High Availability Mode. The default is None and all the options are dimmed. Select Active/Active DPI to activate standard HA configuration and hardware failover functionality, with the option of enabling Stateful HA and Active/Active DPI. A new tab, HA Interfaces, appears and the Enable Stateful Synchronization option is dimmed, but enabled automatically for Active/Active DPI.

3
Optionally, to back up the settings automatically when you upgrade the firmware version, select Generate/Overwrite Secondary Firmware and Settings When Upgrading Firmware. This option is disabled by default.
4
Ensure Enable Preempt Mode is not selected. Preempt mode is recommended to be disabled when enabling Stateful Synchronization, because preempt mode can be over-aggressive about failing over to the Secondary appliance. This option is disabled by default.
5
To allow the Primary and Secondary appliances to share a single MAC address, select Enable Virtual MAC. This greatly simplifies the process of updating network ARP tables and caches when a failover occurs. Only the switch to which the two appliances are connected needs to be notified. All outside devices will continue to route to the single shared MAC address. This option is disabled by default.
6
Click the HA Devices tab to configure the Primary and Secondary appliance serial number.

7
Enter the serial number for the Secondary device in the Secondary Device Serial Number field.

The serial number for the Primary device is populated automatically and cannot be changed. For the Secondary unit, you can find the serial number on the back of the SonicWall security appliance or in the System > Status page.

8
Click the HA Interfaces tab to specify the interfaces that will be used for transferring data between the two units during Active/Active DPI processing.

* 
NOTE: SonicWall High Availability cannot be configured using the built-in wireless interface, nor can it be configured using Dynamic WAN interfaces.

Only unassigned, available interfaces appear in the drop-down menus.

9
Select the Primary Active/Active DPI interface number from the Active/Active DPI Interface drop-down menu. This option is dimmed if the appliance detects that the interface is already configured.
10
Select the Secondary Active/Active DPI interface number from the Active/Active DPI Interface 2 drop-down menu This interface is used for transferring data between the two units during Active/Active DPI processing.

The connected interfaces must be the same number on both appliances, and must initially appear as unused, unassigned interfaces in the Network > Interfaces page. For example, you could connect X5 on the Primary unit to X5 on the Secondary if X5 is an unassigned interface.

After enabling Active/Active DPI, the connected interface will have a Zone assignment of HA Data-Link.

11
When finished with all High Availability configuration, click Apply. All settings are synchronized to the Standby unit, and the Standby unit reboots.

 

Fine Tuning High Availability

High Availability > Advanced

The High Availability > Advanced page provides the ability to fine-tune the High Availability configuration as well as synchronize setting and firmware among the High Availability devices. The High Availability > Advanced page is identical for both Active/Standby and Active/Active configurations. The Heartbeat Interval and Failover Trigger Level settings on the High Availability > Advanced page apply to both the SVRRP heartbeats (Active/Active Clustering heartbeat) and HA heartbeats.

Other settings on High Availability > Advanced page apply only to the HA pairs within the Cluster Nodes.

* 
NOTE: For more information on High Availability, see What Is High Availability? and Active/Standby and Active/Active DPI Prerequisites.

Configuring High Availability > Advanced Settings

The configuration tasks on the High Availability > Advanced page are performed on the Primary unit and then are automatically synchronized to the Secondary.

To configure the settings on the High Availability > Advanced page:
1
Navigate to High Availability > Advanced.

* 
NOTE: The minimum settings shown for the following fields are minimum recommended values. Lower values may cause unnecessary failovers, especially when the SonicWall is under a heavy load. Use higher values if your SonicOS handles a lot of network traffic.
2
The Heartbeat Interval timer controls how often the two units communicate. Specify the interval, in milliseconds, in the Heartbeat Interval (milliseconds) field. The minimum interval is 1000 milliseconds, the maximum is 300000, and the default is 1000.
* 
NOTE: The Heartbeat Interval timer works in conjunction with the Failover Trigger Level timer. For example, if you set the Failover Trigger Level to 5 and the Heartbeat Interval to 1000 milliseconds, it will take 50 seconds without a heartbeat before a failover is triggered.
3
The Failover Trigger Level timer specifies the number of heartbeats the SonicWall will miss before failing over. Specify the number of heartbeats in the Failover Trigger Level (missed heartbeats) field. The minimum number is 4, the maximum is 99, and the default is 5.

This timer is linked to the Heartbeat Interval.

4
The Probe Interval is the time between probes sent to specified IP addresses to ensure the network critical path is reachable. The Probe Interval is used in logical monitoring. Specify the interval, in seconds, in the Probe Interval (seconds) field. The minimum time is 5 seconds, the maximum is 255, and the default is 20.

You can set the Probe IP Address(es) on the High Availability > Monitoring page. See High Availability > Monitoring.

5
The Probe Count is the number of consecutive probes before SonicOS concludes that the network critical path is unavailable or the probe target is unreachable. The Probe Count is used in logical monitoring. Specify the count in the Probe Count field. The minimum number is 3, the maximum is 10, and the default is 3.
6
The Election Delay Time timer can be used to specify an amount of time the SonicWall will wait to consider an interface up and stable. The Election Delay Time timer is useful when dealing with switch ports that have a spanning-tree delay set. Specify the time, in seconds, in the Election Delay Time (seconds) field. The minimum time is 3 seconds, the maximum is 255, and the default is 3.
7
When a failover occurs, the Route Hold-Down Time is the number of seconds the newly-active appliance keeps the dynamic routes it had previously learned in its route table. Specify the time, in seconds, in the Dynamic Route Hold-Down Time (seconds) field. The minimum time is 0 seconds, the maximum is 1200, and the default is 45. In large or complex networks, a larger value may improve network stability during a failover.

This setting is used when a failover occurs on a High Availability pair that is using either RIP or OSPF dynamic routing. When a failover occurs, Dynamic Route Hold-Down Time is the number of seconds the newly-Active appliance keeps the dynamic routes it had previously learned in its route table. During this time, the newly Active appliance relearns the dynamic routes in the network. When the Dynamic Route Hold-Down Time duration expires, SonicOS deletes the old routes and implements the new routes it has learned from RIP or OSPF.

* 
NOTE: The Dynamic Route Hold-Down Time setting is displayed only when the Advanced Routing option is selected on the Network > Routing page.
8
Select Include Certificates/Keys to have the appliances synchronize all Certificates, CRLs, and associated settings (such as CRL auto-import URLs and OCSP settings) are synchronized between the Primary and Secondary units. By default, this option is enabled.
9
You do not need to click Synchronize Settings at this time because all settings will be automatically synchronized to the Standby unit when you click Accept after completing HA configuration. To synchronize all settings on the Active unit to the Standby unit immediately, click Synchronize Settings. The Standby unit will reboot.
10
To have the appliances synchronize all certificates and keys, select Include Certificate/Keys. By default, this option is enabled.
11
Click Synchronize Firmware if you previously uploaded new firmware to your Primary unit while the Secondary unit was offline and it is now online and ready to upgrade to the new firmware. Synchronize Firmware is typically used after taking your Secondary appliance offline while you test a new firmware version on the Primary unit before upgrading both units to it.
12
To force Active/Standby Failover, click Force Active/Standby Failover. This option attempts an Active/Standby HA failover to the secondary unit. Use this action to test the HA failover functionality is working properly.
13
When finished with all High Availability configuration, click Accept. All settings will be synchronized to the Standby unit automatically.

If you enabled Active/Active DPI, the Network > Interfaces page will show that the selected interface for HA Data Interface now belongs to the HA Data-Link zone.

 

Monitoring High Availability

High Availability > Monitoring

On the High Availability > Monitoring page, you can configure both physical and logical interface monitoring. You can configure independent management IP addresses for each unit in the HA Pair, using either LAN or WAN interfaces. You can also configure physical/link monitoring and logical/probe monitoring. For more information about the HA Monitoring settings, see About HA Monitoring.

By enabling physical interface monitoring, you enable link detection for the designated HA interfaces. The link is sensed at the physical layer to determine link viability. Logical monitoring involves configuring the SonicWall to monitor a reliable device on one or more of the connected networks. Failure to periodically communicate with the device by the Active unit in the HA Pair will trigger a failover to the Standby unit. If neither unit in the HA Pair can connect to the device, no action will be taken.

The Primary and Secondary IP addresses configured on this page are used for multiple purposes:

As independent management addresses for each unit (supported on all physical interfaces)
To allow synchronization of licenses between the Standby unit and the SonicWall licensing server
As the source IP addresses for the probe pings sent out during logical monitoring

Configuring unique management IP addresses for both units in the HA Pair allows you to log in to each unit independently for management purposes. Note that non-management traffic is ignored if it is sent to one of these IP addresses. The Primary and Secondary SonicWall security appliances’ unique LAN IP addresses cannot act as an active gateway; all systems connected to the internal LAN will need to use the virtual LAN IP address as their gateway.

The management IP address of the Secondary/Standby unit is used to allow license synchronization with the SonicWall licensing server, which handles licensing on a per-appliance basis (not per-HA Pair). Even if the Secondary unit was already registered on MySonicWall before creating the HA association, you must use the link on the System > Licenses page to connect to the SonicWall server while accessing the Secondary appliance through its management IP address.

When using logical monitoring, the HA Pair will ping the specified Logical Probe IP address target from the Primary as well as from the Secondary SonicWall. The IP address set in the Primary IP Address or Secondary IP Address field is used as the source IP address for the ping. If both units can successfully ping the target, no failover occurs. If both cannot successfully ping the target, no failover occurs, as the SonicWalls will assume that the problem is with the target, and not the SonicWalls. But, if one SonicWall can ping the target but the other SonicWall cannot, the HA Pair will failover to the SonicWall that can ping the target.

Topics:

Configuring the High Availability > Monitoring Page Settings

The configuration tasks on the High Availability > Monitoring page are performed on the Primary unit and then are synchronized automatically to the Secondary.

Topics:

Basic Procedure

To set the independent LAN management IP addresses and configure physical and/or logical interface monitoring:
1
Navigate to High Availability > Monitoring.

2
For the View IP Version option, select either IPv4 or IPv6.
3
Click the Configure icon for an interface on the LAN, such as X0. The Edit HA Monitoring dialog displays.

.

4
To enable link detection between the designated HA interfaces on the Primary and Secondary units, leave the Enable Physical Interface Monitoring check box selected.
* 
NOTE: In the following options, the IP Address will be either IPv4 or IPv6, depending on your selection in Step 2.
5
In the Primary IP<v4/v6> Address field, enter the unique LAN management IP address of the Primary unit.
6
In the Secondary IP<v4/v6> Address field, enter the unique LAN management IP address of the Secondary unit.
7
Select the Allow Management on Primary/Secondary IP<v4/v6> Address check box. When this option is enabled for an interface, a green icon appears in the interface’s Management column in the Monitoring Settings table on the High Availability > Monitoring page. Management is only allowed on an interface when this option is enabled.
8
Optionally, select Logical Probe IP<v4/v6> Address. In its field, enter the IP address of a downstream device on the LAN network that should be monitored for connectivity. Typically, this should be a downstream router or server. (If probing is desired on the WAN side, an upstream device should be used.)

The Primary and Secondary appliances will regularly ping this probe IP address. If both can successfully ping the target, no failover occurs. If neither can successfully ping the target, no failover occurs, because it is assumed that the problem is with the target, and not the SonicWall appliances. But, if one appliance can ping the target but the other appliance cannot, failover will occur to the appliance that can ping the target.

The Primary IP Address and Secondary IP Address fields must be configured with independent IP addresses on a LAN interface, such as X0, (or a WAN interface, such as X1, for probing on the WAN) to allow logical probing to function correctly.

9
Optionally, to manually specify the virtual MAC address for the interface, select Override Virtual MAC and enter the MAC address in the field. The format for the MAC address is six pairs of hexadecimal numbers separated by colons, such as A1:B2:C3:d4:e5:f6. Care must be taken when choosing the Virtual MAC address to prevent configuration errors.

When the Enable Virtual MAC checkbox is selected on the High Availability> Advanced page, the SonicOS firmware automatically generates a Virtual MAC address for all interfaces. Allowing the SonicOS firmware to generate the Virtual MAC address eliminates the possibility of configuration errors and ensures the uniqueness of the Virtual MAC address, which prevents possible conflicts.

10
Click OK.
11
To configure monitoring on any of the other interfaces, repeat Step 3 through Step 10.

All settings are synchronized to the Standby unit automatically.

Synchronizing Settings

Once you finish configuring the High Availability settings on the Primary SonicWall security appliance, the Primary unit will automatically synchronize the settings to the Secondary unit, causing the Secondary to reboot. You do not need to click the Synchronize Settings button on the High Availability > Advanced page.

Later, when you click Synchronize Settings, it means that you are initiating a full manual synchronization and the Secondary will reboot after synchronizing the preferences. You should see a HA Peer Firewall has been updated message at the bottom of the management interface page.

* 
NOTE: The regular Primary-initiated synchronization (automatic, not manual) is an incremental sync, and does not cause the Secondary to reboot.

By default, the Include Certificate/Keys setting is enabled on the High Availability > Advanced page. This option specifies that Certificates, CRLs and associated settings (such as CRL auto-import URLs and OCSP settings) are synchronized between the Primary and Secondary units. When Local Certificates are copied to the Secondary unit, the associated Private Keys are also copied. Because the connection between the Primary and Secondary units is typically protected, this is generally not a security concern.

* 
TIP: A compromise between the convenience of synchronizing Certificates and the added security of not synchronizing Certificates is to temporarily enable the Include Certificate/Keys setting and manually synchronize the settings, and then disable Include Certificate/Keys.

Verifying Connectivity

To verify that Primary and Secondary SonicWall security appliances are functioning correctly, wait a few minutes, then power off the Primary SonicWall device. The Secondary SonicWall security appliance should quickly take over.

From your management workstation, test connectivity through the Secondary SonicWall by accessing a site on the public Internet.

* 
NOTE: The Secondary SonicWall, when Active, assumes the complete identity of the Primary, including its IP addresses and Ethernet MAC addresses.

Log into the Secondary SonicWall’s unique LAN IP address. The management interface should now display Logged Into: Secondary SonicWall Status: Active in the upper right corner. If all licenses are not already synchronized with the Primary unit, navigate to the System > Licenses page and register this SonicWall security appliance on MySonicWall.com. This allows the SonicWall licensing server to synchronize the licenses.

Now, power the Primary SonicWall back on, wait a few minutes, then log back into the management interface. The management interface should again display Logged Into: Primary SonicWall Status: Active in the upper right corner.

If you are using the Monitor Interfaces feature, experiment with disconnecting each monitored link to ensure that everything is working correctly.

* 
TIP: Successful High Availability synchronization is not logged, only failures are logged.

Forcing Transitions

In some cases, it may be necessary to force a transition from the Active SonicWall to the Standby unit, for example, to force the Primary SonicWall to become Active again after a failure when Preempt Mode has not been enabled, or to force the Secondary SonicWall to become Active in order to do preventive maintenance on the Primary SonicWall.

To force such a transition, it is necessary to interrupt the heartbeat from the currently Active SonicWall. This may be accomplished by disconnecting the Active SonicWall’s LAN port, by shutting off power on the currently Active unit, or by restarting it from the Web management interface. In all of these cases, heartbeats from the Active SonicWall are interrupted, which forces the currently Standby unit to become Active.

To restart the Active SonicWall, log into the Primary SonicWall LAN IP address and click System on the left side of the browser window and then click Restart at the top of the window.

Click Restart SonicWall, then Yes to confirm the restart. Once the Active SonicWall restarts, the other SonicWall in the High Availability pair takes over operation.

* 
NOTE: If the Preempt Mode check box has been selected for the Primary SonicWall, the Primary unit takes over operation from the Secondary unit after the restart is complete.
* 
TIP: SonicWall recommends disabling preempt mode when using Stateful Synchronization. This is because preempt mode can be over-aggressive about failing over to the Secondary appliance.

Verifying High Availability Status

There are several ways to view High Availability status in the SonicOS Enhanced management interface.

Topics:

Receiving Email Alerts About High Availability Status

If you have configured the Primary SonicWall to send email alerts, you receive alert emails when there is a change in the status of the High Availability Pair. For example, when the Secondary SonicWall takes over for the Primary after a failure, an email alert is sent indicating that the Secondary has transitioned from Standby to Active. If the Primary SonicWall subsequently resumes operation after that failure, and Preempt Mode has been enabled, the Primary SonicWall takes over and another email alert is sent to the administrator indicating that the Primary has preempted the Secondary.

Viewing High Availability Events in the Log

The SonicWall also maintains an event log that displays the High Availability events in addition to other status messages and possible security threats. This log may be viewed in the SonicOS management interface or it may be automatically sent to the administrator’s email address. To view the SonicWall log, click Log on the left navigation pane of the management interface.

Verifying Active/Active DPI Configuration

This section describes two methods of verifying the correct configuration of Active/Active DPI, and two “false negatives” that might give the impression that the standby unit is not contributing.

Topics:

Comparing CPU Activity on Both Appliances

As soon as Active/Active DPI is enabled on the Stateful HA pair, you can observe a change in CPU utilization on both appliances. CPU activity goes down on the active unit, and goes up on the standby unit.

To view and compare CPU activity:
1
In two browser windows, log into the Monitoring IP address of each unit, active and standby. For information about configuring HA Monitoring, including individual IP addresses, see Configuring High Availability Monitoring.
2
Navigate to the System > Diagnostics page in both SonicOS management interfaces.

3
On both appliances, select Multi-Core Monitor from the Diagnostic Tools drop-down menu. A real-time Multi-Core Utilization graph displays for both units.

Additional Parameters in TSR

You can tell that Active/Active DPI is correctly configured on your Stateful HA pair by generating a Tech Support Report on the System > Diagnostics page. The following configuration parameters should appear with their correct values in the Tech Support Report:

Enable Active/Active DPI
HA Data Interface configuration
To generate a TSR for this purpose:
1
Log into the Stateful HA pair using the shared IP address.
2
Navigate to the System > Diagnostics page.
3
Under Tech Support Report, click Download Report.

Responses to DPI Matches

Responses, or actions, are always sent out from the active unit of the Stateful HA pair running Active/Active DPI when DPI matches are found in network traffic. Note that this does not indicate that all the processing was performed on the active unit.

Deep Packet Inspection discovers network traffic that matches virus attachments, IPS signatures, Application Firewall policies, and other malware. When a match is made, SonicOS Enhanced performs an action such as dropping the packet or resetting the TCP connection.

Some DPI match actions inject additional TCP packets into the existing stream. For example, when an SMTP session carries a virus attachment, SonicOS sends the SMTP client a “552” error response code, with a message saying “the email attachment contains a virus.” A TCP reset follows the error response code and the connection is terminated.

These additional TCP packets are generated as a result of the DPI processing on the standby firewall. The generated packets are sent to the active firewall over the HA data interface, and are sent out from the active firewall as if the processing occurred on the active firewall. This ensures seamless operation and it appears as if the DPI processing was done on the active firewall.

Logging

If Active/Active DPI is enabled and DPI processing on the standby firewall results in a DPI match action as described in Responses to DPI Matches, then the action is logged on the active unit of the Stateful HA pair, rather than on the standby unit where the match action was detected. This does not indicate that all the processing was performed on the active unit.

High Availability related log events can be viewed in the Log > Log Monitor page.

IPv6 High Availability Monitoring

For complete information on the SonicOS implementation of IPv6, see the About IPv6.

IPv6 High Availability (HA) Monitoring is implemented as an extension of HA Monitoring in IPv4. After configuring HA Monitoring for IPv6, both the primary and secondary appliances can be managed from the IPv6 monitoring address, and IPv6 Probing is capable of detecting the network status of HA pairs.

IPv6 and IPv4 radio buttons display in the High Availability > Monitoring page, toggle between the two views for easy configuration of both IP versions:

The IPv6 HA Monitoring configuration page is inherited from IPv4, so the configuration procedures are almost identical. Just select the IPv6 radio button and refer to the About High Availability for configuration details.

Things to Consider

Consider the following when configuring IPv6 HA Monitoring:

The Physical/Link Monitoring and Virtual MAC check boxes are greyed out because they are layer two properties. That is, the properties are used by both IPv4 and IPv6, so you have to configure them in the IPv4 monitoring page.
The primary/secondary IPv6 address must be in the same subnet of the interface, and it can not be same as the global IP and Link-Local-IP of the primary/secondary appliance.
If the primary/secondary monitoring IP is set to (not ::), then they cannot be the same.
If the Management check box is enabled, then primary/backup monitoring IP cannot be unspecified (that is, ::).
If the probe check box is enabled, then the probe IP cannot be unspecified.