"The What?" - In this post I want to cover securing the BGP routing protocol on Cisco IOS. "The Why?" - Securing BGP aides in deterring commonly known TCP threats. As a reminder BGP uses TCP port 179. Since BGP uses TCP it is vulnerable to any known TCP threats, specifically these major ones: DoS: a malicious attacker sends unnecessary traffic to saturate the device control plane resources in an attempt to deter the BGP service. Route Manipulation: an attacker modifies BGP