From: devecchio (devecchio.turner@sbcglobal.net)
Date: Sat Jul 15 2006 - 16:06:53 ART
Team,
This tasks states that I should not provide transit services to any of AS 54
customers.however AS 100 should still have reachability. I configured an
as-path list only allowing locally-originated routes ^$ to AS200. The book
suggest my permit list should resemble
Ip as-path access-list 1 permit _54$. Am I right by concluding that since I
am only allowing _54$ out AS200 will never see AS100 in the path and
therefore will not have a way to get there...It could be done both ways..but
the first is a little more complex.advertise the routes, just don't tell
them how to get there...
I have the following config on r6:
router bgp 100
no synchronization
bgp log-neighbor-changes
neighbor 54.1.1.254 remote-as 54
neighbor 141.1.123.2 remote-as 200
neighbor 141.1.123.2 ebgp-multihop 255
neighbor 141.1.123.2 route-map no_trans out
no auto-summary
!
ip http server
ip classless
!
ip as-path access-list 2 permit ^$
!
!
access-list 1 permit 0.0.0.0 255.255.254.0
!
route-map no_trans permit 10
match as-path 2
Rack1R6#
Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down
State/PfxRcd
54.1.1.254 4 54 47 46 12 0 0 00:40:04 8
141.1.123.2 4 200 21 24 12 0 0 00:16:01 3
Rack1R6#
Rack1R6#show ip bgp
BGP table version is 12, local router ID is 150.1.6.6
Status codes: s suppressed, d damped, h history, * valid, > best, i -
internal,
r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
*> 112.0.0.0 54.1.1.254 0 0 54 50 60 i
*> 113.0.0.0 54.1.1.254 0 0 54 50 60 i
*> 114.0.0.0 54.1.1.254 0 0 54 i
*> 115.0.0.0 54.1.1.254 0 0 54 i
*> 116.0.0.0 54.1.1.254 0 0 54 i
*> 117.0.0.0 54.1.1.254 0 0 54 i
*> 118.0.0.0 54.1.1.254 0 0 54 i
*> 119.0.0.0 54.1.1.254 0 0 54 i
*> 205.90.31.0 141.1.123.2 0 200 254 ?
*> 220.20.3.0 141.1.123.2 0 200 254 ?
*> 222.22.2.0 141.1.123.2 0 200 254 ?
Rack1R6#
This is what I have on r2
Rack1R2#show ip bgp sum
Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down
State/PfxRcd
141.1.0.5 4 300 31 36 20 0 0 00:28:00 0
141.1.36.6 4 100 25 22 20 0 0 00:17:04 0
141.1.123.1 4 200 38 44 20 0 0 00:29:32 3
Rack1R2#
Rack1R2#show ip bgp
Network Next Hop Metric LocPrf Weight Path
*>i205.90.31.0 192.10.1.254 0 100 0 254 ?
*>i220.20.3.0 192.10.1.254 0 100 0 254 ?
*>i222.22.2.0 192.10.1.254 0 100 0 254 ?
Rack1R2#
This archive was generated by hypermail 2.1.4 : Tue Aug 01 2006 - 07:13:47 ART