Next Hop Self Command on Juniper Routers
When an eBGP route advertised to vie iBGP, normally the next-hop of the route stay unchanged. This behaviour causes unknown destinations at the iBGP peer. The route and the next-hop is in another network and there is no information to reach this next-hop.
To overcome this issue, a routing policy that provide “next-hop self” behaviour can be used.
Below, we will show this conffiguration with an example.
Here, there are to steps to apply next-hop self characristic to the router. These are:
1. Create the Routing Policy at the Router
2. Apply the Routing Policy to the Protocol
Let’s start to configure next-hop self. By the way, for our topology, we will configure this, only on RouterA1.
Step 1 – Create the Routing Policy
Step 2 – Create the Routing Policy
Before this configuration, RouterA2 can not reach the network between RouterB1 and RouterB2. Because as a netxt-hop it has the address of RouterB1’s ip address. But it do not know how to reach this next-hop.
After the configuration, Router A2 received this route with the next-hop of its neighbour RouterA1. And after that, it can reach the network between RouterB1 and RouterB2 via its neighbour.