Configuring Router Advertisement Settings

Router Advertisement allows IPv6 routers to advertise DNS recursive server addresses to IPv6 hosts. Router Advertisement-based DNS configuration is a useful, optional alternative in networks where an IPv6 host's address is autoconfigured through IPv6 stateless address autoconfiguration, and where the delays in acquiring server addresses and communicating with the servers are critical. Router Advertisement allows the host to acquire the nearest server addresses on every link. Furthermore, it learns these addresses from the same RA message that provides configuration information for the link, thereby avoiding an additional protocol run. This can be beneficial in some mobile environments, such as with Mobile IPv6. SonicWall’s implementation of IPv6 is full conformable with RFC 4861 in Router and Prefix Discovery.

Router Advertisement can only be enabled when interface is under Static mode.

To configure Router Advertisement for an IPv6 interface

1. Navigate to Network > System > Interfaces > Interfaces Settings.

2. On the Interfaces Settings page, click IPv6.

3. Hover over an interface that you want to configure and click the Edit icon. The Edit Interface dialog box is displayed.

4. Click the Router Advertisement tab.

5. In the Router Advertisement Settings section, select Enable Router Advertisement to make this an advertising interface that distributes network and prefix information.

6. Optionally, you can modify the following Router Advertisement settings:

   • Router Adv Interval Range (seconds) – Enter the time interval allowed between unsolicited multicast Router Advertisements sent from the interface, in seconds. Advertisements are sent at a random value between the minimum and maximum interval:

     • Minimum interval – Enter the shortest interval allowed between Router Advertisements. The minimum time is 3 seconds, the maximum is 1350 seconds, and the default minimum time is 200 seconds.

     • Maximum interval – Enter the longest interval allowed between Router Advertisements. The minimum time is 4 seconds, the maximum is 1800 seconds, and the default maximum time is 600 seconds.

   • Link MTU – Enter the recommended MTU for the interface link. The minimum value is 0, the maximum value is 99999, and the default value is 0, which means the firewall does not advertise link MTU for the link.

   • Reachable Time (seconds) – Enter the time that a node assumes a neighbor is reachable after having received a reachability confirmation. The minimum value is 0, the maximum value is 9999999999, and the default value is 0, which means this parameter is unspecified by this firewall.

   • Retrans Time – Enter the time between retransmitted Neighbor Solicitation messages. The minimum value is 0, the maximum value is 9999999999, and the default value is 0, which means this parameter is unspecified by this firewall.

   • Current Hop Limit – Enter the default value that should be placed in the Hop Count field of the IP header for outgoing IP packets. The minimum value is 0, which means this parameter is unspecified by this firewall; the maximum value is 255; and the default value is 64.

   • Router Lifetime (seconds) – Enter the lifetime when the firewall is accepted as a default router. The minimum value is 0 seconds, which means that the router is not a default router; the maximum time is 9000 seconds, and the default value is 1800 seconds.

   • Router Preference – Indicates whether the advertising default router should be preferred over other default routers. Select High, Medium (default), or Low from the drop-down menu.

7. Select Managed to set the managed address configuration flag in the Router Advertisement message. If set, the flag indicates that IPv6 addresses are available through Dynamic Host Configuration Protocol.

8. Select Other Configuration to set the Other configuration flag in Router Advertisement message. If set, the flag indicates that other configuration information is available through Dynamic Host Configuration Protocol.

9. Click OK.