bgp is...

a horse of a different color...

                                         we're not in kansas anymore...

whoops... why didn't someone just say things you counted on before with routing protocols would suddenly disappear with bgp...

that's all...

triangles still have three sides... don't they?

along came regex...

 or, how i learned to filter routes based on their origin...


as300(config)#ip as-path access-list 1 deny ^100$
as300(config)#ip as-path access-list 1 permit .*


you want to reference this... http://blog.ine.com/tag/as-path/

and thank brian for it...

^ means begin with 100 and $ means end with 100, or match all paths sourced from 100

.* means permit all else that wasn't matched by the deny...

as300#sh ip as-path-access-list
AS path access list 1
     deny ^100$
     permit .*

check it first

as65000#sh ip route bgp         

Gateway of last resort is not set

      10.0.0.0/8 is variably subnetted, 4 subnets, 2 masks
B        10.1.1.0/24 [20/0] via 172.24.1.17, 00:01:21
B        10.2.2.0/24 [20/0] via 172.24.1.17, 01:38:19


then apply it as a neighbor statement in bgp...

as300(config)#router bgp 300
as300(config-router)#neighbor 172.24.1.18 filter-list 1 out

kill bgp softly...

as300#clear ip bgp * soft
as300#

as65000#sh ip route bgp

Gateway of last resort is not set

      10.0.0.0/8 is variably subnetted, 3 subnets, 2 masks
B        10.2.2.0/24 [20/0] via 172.24.1.17, 01:39:52

all the way gone...

what is the law?

only advertised networks are doable...