Do any Cisco IOS/XE/XR systems support the updated TCP security option TCP-AO (option kind 29)? It'd be nice to be able to use it.

It's defined in RFC 5925, and is meant to obsolete RFC 2385, "Protection of BGP Sessions via the TCP MD5 Signature Option".

I can't find any good references for it. Even descriptions of BGP md5 authentication (tcp option kind 19) tend to gloss over details.

Is there a method to authenticate with AO instead of md5? Does Cisco even recognize it anywhere?

2 Answers 2


Currently no for all three, and I don't think there is support in the popular gear in general.


IOS-XR supports TCP-AO from 6.5.1 onwards

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.