Filtering Routes from a Dynamic Routing Protocol

This article describes the methodology to exclude a particular network route from router advertisements so that the specified neighbor does not receive the identified route.

There is a need to not advertise a specific network to a specific peer so that the network in question does not get inserted in the routing protocol's database on the remote peer (for example: a security concern or contractual need).

In RIP one can stop the propagation of a specific network via Distribute Lists.

Identify the SonicWall(s) best suited to stop the spread of the route through the network, the following configuration will be carried out on this/these device(s).

Requirements:

A Tunnel Interface VPN has been set up and Virtual Tunnel Interfaces to be used by the routing protocol have been created.
RIP has been enabled on the Virtual Tunnel Interfaces and routes are populating properly across the network.

Procedure:

1. Connect to the SonicWall via SSH or Console.
   Enter configuration mode under Routing > RIP:
   configure terminal 
   routing
   rip
   configure terminal
   
   
2. Configure an ACL to match the desired route:
   access-list TEST deny 192.168.168.0/24
   access-list TEST permit any
   
   
3. Apply the ACL via a distribute-list towards the desired Virtual Tunnel Interface:
   router rip
   distribute-list TEST out Virtual_Ti_name

 
CLI Commands in full from connection:

configure terminal
routing
rip
configure terminal
access-list TEST deny 192.168.168.0/24
access-list TEST permit any

router rip
distribute-list TEST out Virtual_Ti_name