BGP Examples

[DAVID APAW]

The subnet 192.168.25.0 is not being advertised. Can some one help me?
8.8.8.9 ----- This is a loopback IP address
20.20.15.21 ----- next hop for ASN 277



router bgp 233
 bgp log-neighbor-changes
 network 8.8.8.9 mask 255.255.255.255
 network 192.168.25.0 mask 255.255.255.0
 neighbor 20.20.15.21 remote-as 277
 neighbor 20.20.15.21 route-map SETLOCAL in
 neighbor 20.20.15.21 filter-list 10 out
 neighbor 8.8.8.9 remote-as 277
 neighbor 8.8.8.9 password 7 132846115F5D40787D
 neighbor 8.8.8.9 ebgp-multihop 15
 neighbor 192.168.25.8 remote-as 233
 neighbor 192.168.25.8 password 7 143A430858556E7972
 neighbor 192.168.25.8 next-hop-self
 maximum-paths 6
!
ip forward-protocol nd
!
ip as-path access-list 5 permit ^277$
ip as-path access-list 10 permit ^$

!
ip route 0.0.0.0 0.0.0.0 20.20.15.21 track 16
ip route 0.0.0.0 0.0.0.0 20.20.15.21
!
ip sla enable timestamp
!
route-map SETLOCAL permit 10
 set local-preference 200

[Jon Marshall]

What does a "sh ip route 192.168.25.0" show ?

Jon

[DAVID APAW]

Router-A#sho ip route
Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP
       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2
       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
       ia - IS-IS inter area, * - candidate default, U - per-user static route
       o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP
       + - replicated route, % - next hop override

Gateway of last resort is 20.20.15.21 to network 0.0.0.0

S*    0.0.0.0/0 [1/0] via 20.20.15.21
      20.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C        20.20.15.20/30 is directly connected, GigabitEthernet0/2
L        20.20.15.22/32 is directly connected, GigabitEthernet0/2
      74.0.0.0/30 is subnetted, 1 subnets
B        74.18.12.14 [200/0] via 192.168.25.8, 22:06:50
C     192.168.25.0/24 is directly connected, GigabitEthernet0/1
      192.168.25.0/32 is subnetted, 1 subnets
L        192.168.25.1 is directly connected, GigabitEthernet0/1

Router-A#sho ip route 192.168.25.0
Routing entry for 192.168.25.0/32, 1 known subnets
  Attached (1 connections)
  Redistributing via bgp 233
L        192.168.25.1 is directly connected, GigabitEthernet0/1
Router-A#

[Jon Marshall]

Sorry just reread your original post.

Why are you peering with the same AS twice ?

Can you post "sh ip bgp summary".

Jon

[Vinit Jain]

Adding to what just Jon mentioned, you are advertising the same loopback with which you are peering (8.8.8.9). Is that the correct peering IP that you have.

Also, can you please share the below output:

- show ip bgp nei 20.20.15.21 advertised-routes

Vinit

[DAVID APAW]

8.8.8.9 is the multihop loopback. We are peering with 20.20.15.21

[Vinit Jain]

Hello David

Below is what i was pointing out. 

router bgp 233
 bgp log-neighbor-changes
 network 8.8.8.9 mask 255.255.255.255
 network 192.168.25.0 mask 255.255.255.0
 neighbor 20.20.15.21 remote-as 277
 neighbor 20.20.15.21 route-map SETLOCAL in
 neighbor 20.20.15.21 filter-list 10 out
 neighbor 8.8.8.9 remote-as 277
 neighbor 8.8.8.9 password 7 132846115F5D40787D
 neighbor 8.8.8.9 ebgp-multihop 15
 neighbor 192.168.25.8 remote-as 233
 neighbor 192.168.25.8 password 7 143A430858556E7972
 neighbor 192.168.25.8 next-hop-self
 maximum-paths 6

You might want to verify that network statement, which i dont think is correct.

[DAVID APAW]

The IP address 192.168.25.8 is a second router (Router-B) that connects to another ISP (The BGP is a multi-home). Please focus on  just Router-A for now.

Router-A#sho ip bgp summary
BGP router identifier 192.168.25.1, local AS number 233
BGP table version is 10, main routing table version 10
4 network entries using 592 bytes of memory
5 path entries using 320 bytes of memory
4/4 BGP path/bestpath attribute entries using 544 bytes of memory
1 BGP AS-PATH entries using 24 bytes of memory
0 BGP route-map cache entries using 0 bytes of memory
0 BGP filter-list cache entries using 0 bytes of memory
BGP using 1480 total bytes of memory
BGP activity 5/1 prefixes, 8/3 paths, scan interval 60 secs

Neighbor        V           AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down  State/PfxRcd
   20.20.15.21  4         277       0       0        1    0    0 21:48:53 Active
    8.8.8.9     4         277       0       0        1    0    0 never    Idle
192.168.25.8    4        233    1371    1510       10    0    0 22:43:34        3
Router-A#

[Jon Marshall]

You don't have a neighborship established yet so you won't be advertising any routes.

You need to work out why it is not establishing ie. "debug ip bgp" is a useful command to use.

Can you ping the neighbor IP address ?

Jon

[Jon Marshall]

After you configured the filtering did you do a -

"clear ip bgp 20.20.15.21 soft out"

Jon

[paul driver]

Hello

that subnet will not be advertised until the peering is established

and you cannot peer to loopback if bgp doesn't have NLRI to it

Via a static route or IGP just advertising it in bgp will not work

so when you can reach the loopback then the peering will establish and the 192.168.25.0/24 Subnet will be advertised

Res

paul