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Knowledge Base

Overview and Configuration of Packet Mirror in SonicOS 5.9 & Above

Description

This article explains following information regarding Packet Mirror,

  • What is Packet Mirror?
  • Supported platforms for Packet Mirror
  • How Does Packet Mirror Work?
  • Configuring Mirror Settings

What is Packet Mirror?

Packet mirroring is the process of sending a copy of packets seen on one interface to another interface or to a remote  SonicWall appliance. There are two aspects of mirroring:

Classification   Refers to identifying a selected set of packets to be mirrored. Incoming and outgoing packets to and from an interface are matched against a filter. If matched, the mirror action is applied.

Action   Refers to sending a copy of the selected packets to a port or a remote destination. Packets matching a classification filter are sent to one of the mirror destinations. A particular mirror destination is part of the action identifier.

Resolution

Supported Platforms for Packet Mirror:

On all SonicWall NSA Series appliances running SonicOS Enhanced 5.6 or higher, packet mirroring is fully supported. On SonicWall TZ Series appliances running SonicOS Enhanced 5.6 or higher, packet mirroring is partially supported, as follows:

 Local mirroring is not supported. Remote mirroring is supported for both sending and receiving mirrored packets.

How Does Packet Mirror Work?

Every classification filter is associated with an action identifier. Up to two action identifiers can be defined, supporting two mirror destinations (a physical port on the same firewall and/or a remote SonicWall firewall). The action identifiers determine how a packet is mirrored.

The following types of action identifiers are supported:

 Send a copy to a physical port.

 Encapsulate the packet and send it to a remote SonicWall appliance.

 Send a copy to a physical port with a VLAN configured. Classification is performed on the Monitor Filter and Advanced Monitor Filter tab of the Packet Monitor Configuration window.

A local SonicWall firewall can be configured to receive remotely mirrored traffic from a remote SonicWall firewall. At the local firewall, received mirrored traffic can either be saved in the capture buffer or sent to another local interface. This is configured in the (Receiver Remote Mirror Settings) section on the Mirror tab of the Packet Monitor Configuration window.

SonicOS Enhanced 5.6 and higher supports the following packet mirroring options:

 Mirror packets to a specified interface (Local Mirroring).

  Mirror only selected traffic.

 Mirror SSL decrypted traffic.

 Mirror complete packets including Layer 2 and Layer 3 headers as well as the payload.

 Mirror packets to a remote  SonicWall network security appliance (Remote Mirroring Tx).

 Receive mirrored packets from a remote  SonicWall appliance (Remote Mirroring Rx).


Configuring Mirror Settings:

This section describes how to configure Packet Monitor mirror settings. Mirror settings provide a way to send packets to a different physical port of the same firewall or to send packets to, or receive them from, a remote SonicWall firewall.

To configure mirror settings, perform the following steps:

Step 1: Navigate to the Dashboard | Packet Monitor page and click Configure.

Step 2: In the Packet Monitor Configuration window, click the Mirror tab.

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Step 3: Under Mirror Settings, type the desired maximum mirror rate into the Maximum mirror rate (in kilobits per second) field. If this rate is exceeded during mirroring, the excess packets will not be mirrored and will be counted as skipped packets. This rate applies to both local and remote mirroring. The default and minimum value is 100 kbps, and the maximum is 1 Gbps.

Step 4: Select the Mirror only IP packets checkbox to prevent mirroring of other Ether type packets, such as ARP or PPPoE. If selected, this option overrides any non-IP Ether types selected on the Monitor Filter tab.

Step 5: Under Local Mirror Settings, select the destination interface for locally mirrored packets in the Mirror filtered packets to Interface (NSA platforms only) drop-down list.

Step 6: Under Remote Mirror Settings (Sender), in the Mirror filtered packets to remote SonicWall firewall (IP Address) field, type the IP address of the remote SonicWall to which mirrored packets will be sent.

Note: The remote SonicWall must be configured to receive the mirrored packets.

Step 7: In the Encrypt remote mirrored packets via IPSec (preshared key-IKE) field, type the pre-shared key to be used to encrypt traffic when sending mirrored packets to the remote SonicWall. Configuring this field enables an IPSec transport mode tunnel between this appliance and the remote SonicWall. This pre-shared key is used by IKE to negotiate the IPSec keys.

Note: The Encrypt remote mirrored packets via IPSec (preshared key-IKE) option is inactive in SonicOS Enhanced 5.6, and will be supported in a future release.

Step 8: Under Remote Mirror Settings (Receiver), in the Receive mirrored packets from remote SonicWall firewall (IP Address) field, type the IP address of the remote SonicWall from which mirrored packets will be received.

Note: The remote SonicWall must be configured to send the mirrored packets.

Step 9: In the Decrypt remote mirrored packets via IPSec (preshared key-IKE) field, type the pre-shared key to be used to decrypt traffic when receiving mirrored packets from the remote SonicWall. Configuring this field enables an IPSec transport mode tunnel between this appliance and the remote SonicWall. This pre-shared key is used by IKE to negotiate the IPSec keys.

Note: The Decrypt remote mirrored packets via IPSec (preshared key-IKE) option is inactive in SonicOS Enhanced 5.6, and will be supported in a future release.

Step 10: To mirror received packets to another interface on the local  SonicWall, select the interface from the Send received remote mirrored packets to Interface (NSA platforms only) drop-down list.

Step 11: To save received packets in the local capture buffer, select the Send received remote mirrored packets to capture buffer checkbox. This option is independent of sending received packets to another interface, and both can be enabled if desired.

Step 12: To save your settings and exit the configuration window, click OK.