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New Member

Regexp to filter all private ASNs

Hello everybody,

I want to filter all prefixes that have private ASNs in their AS path and I want to achive this via an ip as-path access-list. (neighbor x.x.x.x remove-private-as isn't an option)

What would a regexp have to look like that filters all ASNs from 64512-65535 ?

Regards,

Dirk

1 ACCEPTED SOLUTION

Accepted Solutions
Silver

Re: Regexp to filter all private ASNs

Dirik

I think this can solve your problem.

ip as-path access-list 1 permit (_64[6-9][0-9][0-9]_|_65[0-9][0-9][0-9]_)

regards

shivlu

3 REPLIES
Silver

Re: Regexp to filter all private ASNs

Dirik

I think this can solve your problem.

ip as-path access-list 1 permit (_64[6-9][0-9][0-9]_|_65[0-9][0-9][0-9]_)

regards

shivlu

New Member

Re: Regexp to filter all private ASNs

Hello Shivlu,

Thank you very much for your reply, it's the right approach - it's just missing the range from 64512-64599.

I found this here:

ip as-path access-list 150 permit _(6451[2-9]|645[2-9][0-9]|64[6-9][0-9][0-9])_

ip as-path access-list 150 permit _(65[0-4][0-9][0-9]|655[0-2][0-9]|6553[0-5])_

on http://www.merit.edu/mail.archives/nanog/2003-01/msg00365.html

Kind regards,

Dirk

Silver

Re: Regexp to filter all private ASNs

Thanks for sending me the link of good community.

regards

shivlu

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