packet filtering on BGP communities

[william jackson]

Hi all

I want to achieve the following scenario:

I have a BGP feed that gives me routes with community X.

I have an input ACL on an interface.

I want to be able to say:

if src or dst of packet = any route with community x then drop

I can do this with FBF in junos, can I do this on IOS-XR?

[serge123]

Hi,

You could use route policy

Check this link for more details:

http://www.cisco.com/en/US/docs/ios_xr_sw/iosxr_r3.0/routing/command/reference/rr3plcy.html#wp1010243

[william jackson]

Thanks serge, but this is not what I want.

The route-policy only apply at the routing level, what I want is to packet filter based on routes having certain communities.

[Serge Krier · Accepted solution]

Hi William,

I think you can use technique similar to RTBH :

http://www.cisco.com/en/US/prod/collateral/iosswrel/ps6537/ps6586/ps6642/prod_white_paper0900aecd80313fac.pdf

by using rpl to set the next-hop to a /32 address statically routed to NULL.

For source address match, you combine this with RPF.

Hope it helps,

Serge.

[william jackson]

Thanks serge

thats just what I need.