To troubleshoot idle state, which step is recommended?

• A. Restart the router.
• B. Disable IGP.
• C. Change the BGP password.
• D. Ensure that the neighbor announces the route via an IGP and verify that you have not entered an incorrect IP address in the neighbor statement.

Answer: (D)

Troubleshooting idle state is about ensuring the BGP peer can be reached to establish the TCP session. Idle means the session isn’t attempting at all; the router hasn’t even started the connection. The best step is to verify reachability to the neighbor: confirm that the neighbor’s IP is reachable via the IGP and that the neighbor statement uses the correct IP address. Without an IGP route to the neighbor, the router cannot open a TCP connection, so BGP stays in idle. If the IGP isn’t advertising the neighbor’s network, adjust routing or add a static path to enable reachability. If there’s a mismatch in the IP address in the neighbor configuration, correct it to ensure the correct neighbor is targeted. This directly addresses why the session remains idle. Other options don’t tackle reachability: restarting doesn't fix misconfig or missing routes; disabling IGP disrupts routing; changing the BGP password affects authentication after the session is established, not the initial establishment.