AS-PATH Filtering

[intertouch]

Hi there,

I have two E3 lines connected to AS9930 and AS4788. I have implemented the AS-path filtering:

ip as-path access-list 104 permit ^9933$

ip as-path access-list 104 permit _9933$

!

!

route-map itt_in-TIME permit 10

match as-path 104

!

!

After I implemented it, the ip prefixes just stop coming via AS9930. Why is that so?

[olorunloba]

How is this implemented? If this is implemented as inbound filter, then you might not get prefixes.

The first line

ip as-path access-list 104 permit ^9933$

matches route that originate from the directly connected AS 9933. But since you are not connected to this AS, then this line would match nothing.

The second line

ip as-path access-list 104 permit _9933$

matches routes that originated from AS 9933. If AS 9930 does not have entries for AS 9933 in uts table, then nothing will be recieved from AS 9930.

Hope this helps