In the iBGP example, which command configures the neighbor 172.16.23.2 with remote-as 65000?

• A. R3 (config)# router bgp 65000; R3 (config-router)# neighbor 172.16.23.2 remote-as 65000
• B. R2 (config)# router bgp 65000; R2 (config-router)# neighbor 172.16.23.2 remote-as 65000
• C. R3 (config)# router bgp 65000; R3 (config-router)# neighbor 172.16.23.2 remote-as 65001
• D. R3 (config)# router bgp 65001; R3 (config-router)# neighbor 172.16.23.2 remote-as 65000

Answer: (A)

In iBGP, peers must reside in the same autonomous system, so the local BGP process is started with the same AS as the neighbor, and the neighbor statement uses remote-as equal to that AS. Configuring router bgp 65000 on the local router and then setting neighbor 172.16.23.2 remote-as 65000 tells the router that the neighbor is in the same AS and should be treated as an iBGP neighbor. That alignment of the local AS and the neighbor’s remote-as is what makes this the correct setup.

The other options would misalign the AS numbers—either using a different local AS (which would indicate eBGP) or using a different remote-as value (which would not establish an iBGP session with AS 65000). The essential point is matching the local BGP process AS with the remote-as of the neighbor for iBGP.