I'm having trouble with this AS-Path situation. I have 2 routers (A and B) running iBGP to each other. Each router has a single eBGP connection to a different service provider. ISP-A ISP-B | | A-------B >From ISP A I am receiving partial routes, basically network within its AS. >From ISP B I am receiving full internet routes. Here is the problem: The partial routes from ISP A are summarized, and the routes from ISP may not be summarized. So my router A has an entry for 12.0.0.0/8 and the AS path has 1 entry. Router B receives the 12.0.0.0/8 through iBGP and also more specific routes from ISP-B (12.20.1.0/24, 12.96.0.0/16). In router B the 12.X.X.X BGP entries have the ISP-A AS# as the first entry in the AS-Path. Router B, because of the longest match rule, prefers the Router B-->ISP B path for the more specific networks. I would like to use IP as-path filters to filter incoming updates from ISP-B so not to learn networks originating from ISP-A AS#. What is the regular expression to do this?? ip as-path access-list 20 deny ?????? ^as#_ _as#$ >From sho ip bgp Network Next Hop *> 12.0.0.0 A.A.A.A NEIGHBOR *> 12.0.48.0/20 B.B.B.B NEIGHBOR *> 12.0.252.0/23 B.B.B.B NEIGHBOR Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=16068&t=16068 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]