as-path List regular expression

[snarayanaraju]

Hi experts,

I am practising AS-PATH regular expression.

To allow any at the end of as-path access-list i found that document saying

*.**

But I tried with _ (meaning any starting, ending, paranthesis ) alone. it is

aslo working fine. Shall i use this instead of .* in lan. Is there any

significant difference is there.

example:

ip as-path access-list 1 deny _300$

ip as-path access-list 1 permit _

Thanks in advance

sairam

[Peter Paluch · Accepted solution]

Hi Sairam,

I think you can use the underscore as the "permit any" without problems. For people more used to classical regular expressions, the ".*" syntax is more readable but the underscore works here as well and I believe that there are almost no efficiency differences between evaluating these two expressions.

Best regards,

Peter