CISCO IOS in a Nutshell

Neighbor Authentication

As with other protocols, we can force BGP to authenticate other routers with a password. All passwords are scrambled using an MD5 message digest. On the network in Figure 10-1, we can enable password authentication between office-r1 and office-r2 by adding the password command to our BGP configuration. On office-r1, we add the neighbor ... password command after the neighbor ... remote-as command. You must configure the same password on both routers, or they can’t communicate with BGP. Here’s the configuration for office-r1:

router bgp 3000
  neighbor 192.168.3.2 remote-as 3000
  neighbor 192.168.3.2 password letmein

The same goes for office-r2:

router bgp 3000
  neighbor 192.168.3.1 remote-as 3000
  neighbor 192.168.3.1 password letmein