Hi guys, I'm having this weird issue with BGP and I was wondering if you could help.
Topology: - 2 X cisco 1800 series routers, both connected to 2 different ISPs: Router1 -> ISPA and RouterB -> ISPB - Router1 and Router2 are directly connected - on Router1 receiving only the default route from ISPA - on Router2 receiving customer routes from ISPB - announcing a /23 address block through both ISPA and ISPB (91.195.X.X) The connectivity with ISPA is being done using a /30 subnet (interconnected subnets): ISPA(172.28.164.17/30) -> router1(172.28.164.18/30). Also, I have a /29 public address space on router1 (62.217.X.X) routed through the /30 subnet. The default gw for Router1 received via eBGP is 62.217.w.w and I have added a static route for it: ip route 62.217.w.w 255.255.255.255 172.28.164.17 That's how ISPA has it's network configured and I cannot change anything. The connectivity with ISPB is simple: only a /32 ip address on Router2: 89.149.X.X BGP config Router1: router bgp myASN no synchronization bgp router-id 62.217.X.X bgp log-neighbor-changes network 91.195.X.0 mask 255.255.254.0 neighbor 62.217.X.X remote-as ASN_ISPA neighbor 62.217.X.X ebgp-multihop 8 neighbor 62.217.X.X soft-reconfiguration inbound neighbor 62.217.X.X filter-list 10 out neighbor 91.195.y.1 remote-as myASN neighbor 91.195.y.1 next-hop-self no auto-summary ip as-path access-list 10 permit ^$ BGP config Router2: router bgp myASN no synchronization bgp router-id 89.149.X.X bgp log-neighbor-changes network 91.195.X.0 mask 255.255.254.0 neighbor 89.149.X.X remote-as ASN_ISPB neighbor 89.149.X.X filter-list 10 out neighbor 91.195.z.1 remote-as myASN neighbor 91.195.z.1 next-hop-self no auto-summary ip as-path access-list 10 permit ^$ The issue is after I configure the iBGP relationship between Router1 and Router2: connectivity to the 62.217.X.X/29 subnet on Router1 is lost. It cannot be pinged anymore from outside. The 91.195.X.X/23 is announced correctly through both ISPs and any IP in this /23 subnet is pingable from outside. They only problem is with the 62.217.X.X/29 block that becomes unreachable after configuring the iBGP relationship and I don't understand why this is happening. Sorry for the long post and I hope you'll give me some hints -:) Thanks, John _______________________________________________ cisco-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
