SonicOS 8 IPv6 Tunnel Interfaces (“v6plus”)

Description

v6Plus enables SonicWall firewalls to connect directly to v6Plus ISP services, including automatic notification to the ISP's resetting server when the WAN IPv6 prefix changes.

“v6plus”

What Is “v6plus”?

“v6plus” is an IPv4-over-IPv6 broadband service used by ISPs deploying IPv6-primary access networks. In a “v6plus” environment, the ISP’s access infrastructure is IPv6-only. The customer firewall connects to the ISP’s Border Relay (BR) via an IPv6 tunnel, through which IPv4 traffic is encapsulated and forwarded. The BR decapsulates the traffic at the ISP edge and routes it to the IPv4 internet.

 

“v6plus” Encapsulation Method: SonicWall implements “v6plus” using IPIP tunneling — IPv4-over-IPv6 encapsulation as per RFC 2473 (Generic Packet Tunneling in IPv6). An IPv4-over-IPv6 IPIP tunnel is established between the SonicWall firewall and the Border Relay (BR) operated by JPIX. In the Static IP variant, the customer is assigned a fixed IPv4 address; in the standard service, a shared IPv4 address with port-range allocation is used. As confirmed in the JPIX “v6plus” technical specification (section 6.3), the IPIP method (RFC 2473) is the encapsulation mechanism used for “v6plus” connectivity.

 

A key operational characteristic of “v6plus” is that the customer's WAN IPv6 prefix may be periodically reassigned by the ISP. The ISP maintains a resetting server that must be notified each time the prefix changes — without this notification, the ISP's provisioning system falls out of synchronization and IPv4 connectivity is disrupted.

Note: “v6plus” is a trademark of Japan Internet Xing Co., Ltd.

 

SonicOS 8: SonicOS supports “v6plus” natively as a 4to6 Tunnel Interface type. The Auto Update URL feature automates the prefix change notification process, eliminating the need for manual intervention or external scripts to notify the ISP resetting server.

 

Auto Update URL

The Auto Update URL feature sends an HTTP request to the ISP's resetting server under the following conditions:

  • When the tunnel interface is first configured and brought up
  • When the IPv6 address of the bound WAN interface changes (for example, when the ISP reassigns the WAN IPv6 prefix)
  • Periodically, at a configured interval

 

The following settings control this behavior, configured on the Advanced Tab of the “v6plus” tunnel interface:

  • Update URL — the HTTP endpoint of the ISP's resetting server. This value is provided by the ISP.
  • Update URL Period — controls the periodic notification interval. Set to 0 to send the notification only when the prefix changes (recommended). A non-zero value enables periodic updates; 30 minutes or more is strongly recommended if periodic updates are required.
  • Status indicator — displays the result of the last HTTP request: green (success), yellow (in progress or pending), red (failed).

 

Important:  It is recommended to set Update URL Period to 0. This ensures notifications are sent immediately when the prefix changes and avoids unnecessary traffic to the ISP resetting server.

 

Configuration

For step-by-step configuration instructions, refer to the SonicOS 8 Administration Guide.

https://www.sonicwall.com/techdocs

 

The following settings control this behavior, configured on the Advanced Tab of the v6Plus tunnel interface:

  • Update URL: the HTTP endpoint of the ISP's resetting server. This value is provided by the ISP.
  • Scheduled Update URL Interval controls the periodic notification interval. Set to 0 to send the notification only when the prefix changes (recommended). A non-zero value enables periodic updates; 30 minutes or more is strongly recommended if periodic updates are required.
  • Status indicator displays the result of the last HTTP request: green (success), yellow (in progress or pending or unknow status), red (failed).

Important:  It is strongly recommended to set Update URL Period to 0. This ensures notifications are sent immediately when the prefix changes and avoids unnecessary traffic to the ISP resetting server.

 

For more information on Configuration

For step-by-step configuration instructions, refer to the SonicOS 8 Administration Guide.

https://www.sonicwall.com/support/technical-documentation/docs/sonicos8-system/Content/Interfaces/interfaces-configuring-v6plus.htm

 

Real-World Use Cases

Use Case

Scenario

Outcome

IPv6-Primary ISP, v6Plus Connectivity

A business connects to an ISP that provides v6Plus service over an IPv6-primary access network. The ISP periodically reassigns the customer's WAN IPv6 prefix and requires the firewall to notify its resetting server on each change.

SonicOS 8 is configured with a v6Plus tunnel interface. The Auto Update URL is configured with the ISP's resetting server address. When the WAN IPv6 prefix changes, SonicOS automatically notifies the resetting server, maintaining connectivity without manual intervention.

Dual-ISP Deployment with Mixed Transition Mechanisms

An organization has two broadband connections: one ISP uses DS-Lite and the other uses v6Plus. Both connections are IPv6-primary. The organization requires resilient internet access with automatic failover.

SonicOS 8 supports DS-Lite and v6Plus simultaneously on separate WAN interfaces. Both tunnel interfaces participate in SD-WAN path selection, enabling automatic failover and SLA-based path steering between the two ISP connections.

 

Summary

SonicOS 8 supports v6Plus as a native 4to6 tunnel interface type, enabling SonicWall firewalls to deliver IPv4 internet connectivity over IPv6-primary ISP access networks. The Auto Update URL feature in v6Plus automatically notifies the ISP resetting server when the WAN IPv6 prefix changes. This notification is triggered during tunnel setup, upon prefix changes, or at periodic intervals.

The v6Plus tunnel interface is configured through the 4to6 Tunnel Interface dialog under Network | Interfaces.

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