/31 not allowed on ASA

[jwbensley]

I have just been told that ASAs don't support a /31 assignment on an interface because they don't run IOS. Is this true? Also, can anyone point me at any official documentation stating either way?

All I have found is this [1] which just says "Do Not Use"?

[1] http://www.cisco.com/en/US/docs/security/asa/asa81/config/guide/ports.html#wp1007373

[mvsheik123]

Check if this answers your question..

http://www.cisco.com/en/US/docs/ios/12_2t/12_2t2/feature/guide/ft31addr.html

Thx

MS

[jwbensley]

Hi mvshik123,

Thanks for your prompt response

Thats for IOS 12.2, I don't think ASA's run IOS do they? Don't they run their own ASA OS which is IOS "like"?

Many thanks,

[mvsheik123 · Accepted solution]

Hi,

Routers run IOS s/w - mainly provides rich routing capabilities, where as ASA s/w main purpose is 'security' at the perimeter. Both are with different features and functionality. Being said that at this time /31 is not supported on ASA interface ( I do not have 8.4.x version available on our ASAs, but I don't think this version does not support either).

This is just basic. If you google for the diff, you may be able to find alot of discussions on this.

hth

MS

[jwbensley]

Thanks for that mvsheik123. I have found more useful info confirm no /31's

Still thanks for clearing this up