How to Configure a 6to4 Tunnel to a 6to4 Relay Router

Because of major security issues, by default 6to4 relay router support is disabled in the Solaris operating system. See Considerations for Tunnels to a 6to4 Relay Router and Internet Draft, Security Considerations for 6to4.

Before you enable a tunnel to a 6to4 relay router, you must have completed the following tasks:

• Configured a 6to4 router at your site, as explained in How to Configure a 6to4 Router.

• Reviewed the security issues that are involved in tunneling to a 6to4 relay router.

1. Become superuser on the 6to4 router.

2. Enable a tunnel to the 6to4 relay router by using either of the following formats:

   • Enable a tunnel to an anycast 6to4 relay router.

     # /usr/sbin/6to4relay -e

     The -e option sets up a tunnel between the 6to4 router and an anycast 6to4 relay router. Anycast 6to4 relay routers have the well-known IPv4 address 192.88.99.1. The anycast relay router that is physically nearest to your site becomes the endpoint for the 6to4 tunnel. This relay router then handles packet forwarding between your 6to4 site and a native IPv6 site.

     For detailed information about anycast 6to4 relay routers, refer to RFC 3068, "An Anycast Prefix for 6to4 Relay Routers"

   • Enable a tunnel to a specific 6to4 relay router.

     # /usr/sbin/6to4relay -e -a relay-router-address

     The -a option indicates that a specific router address is to follow. Replace relay-router-address with the IPv4 address of the specific 6to4 relay router with which you want to enable a tunnel.

   The tunnel to the 6to4 relay router remains active until you remove the 6to4 tunnel pseudo-interface.

3. Delete the tunnel to the 6to4 relay router, when no longer needed, by typing the following:

   # /usr/sbin/6to4relay -d

4. (Optional) Make the tunnel to the 6to4 relay router persistent across reboots.

   Your site might have a compelling reason to have the tunnel to the 6to4 relay router reinstated each time the 6to4 router reboots. To support this scenario, you must do the following.

   1. Edit the/etc/default/inetinit file.

      The line that you need to modify is at the end of the file.

   2. Change the “NO” value in the line ACCEPT6TO4RELAY=NO to “YES.”

   3. (Optional) Create a tunnel to a specific 6to4 relay router that persists across reboots.

      For the parameter RELAY6TO4ADDR, change the address 192.88.99.1 to the IPv4 address of the 6to4 relay router that you want to use.

Examples—Getting Status Information About 6to4 Relay Router Support

You can use /usr/bin/6to4relay to find out whether support for 6to4 relay routers is enabled. The next example shows the output when support for 6to4 relay routers is disabled, as is the default in the Solaris operating system:

# /usr/sbin/6to4relay
6to4relay: 6to4 Relay Router communication support is disabled.

When support for 6to4 relay routers is enabled, you receive the following output:

# /usr/sbin/6to4relay
6to4relay: 6to4 Relay Router communication support is enabled.
IPv4 destination address of Relay Router=192.88.99.1