Debug BGP

[Mohd Khairul Nizam]

Hi all,

My BGP is not connecting. I saw this,

05:33:22: BGP: 58.139.93.113 open active, local address 0.0.0.0
05:33:52: BGP: 58.139.93.113 open failed: Connection timed out; remote host not responding
05:35:52: BGP: 58.139.93.113 open active, local address 0.0.0.0
05:36:22: BGP: 58.139.93.113 open failed: Connection timed out; remote host not responding
05:38:22: BGP: 58.139.93.113 open active, local address 0.0.0.0
05:38:52: BGP: 58.139.93.113 open failed: Connection timed out; remote host not responding
05:40:52: BGP: 58.139.93.113 open active, local address 0.0.0.0
05:41:22: BGP: 58.139.93.113 open failed: Connection timed out; remote host not responding

BGP neighbor is 58.a.a.113,  remote AS 23736, external link
  BGP version 4, remote router ID 0.0.0.0
  BGP state = Active
  Last read 05:44:30, hold time is 180, keepalive interval is 60 seconds
  Received 0 messages, 0 notifications, 0 in queue
  Sent 0 messages, 0 notifications, 0 in queue
  Route refresh request: received 0, sent 0
  Default minimum time between advertisement runs is 30 seconds

 For address family: IPv4 Unicast
  BGP table version 1, neighbor version 0
  Index 1, Offset 0, Mask 0x2
  0 accepted prefixes consume 0 bytes
  Prefix advertised 0, suppressed 0, withdrawn 0
  Number of NLRIs in the update sent: max 0, min 0

  Connections established 0; dropped 0
  Last reset never
  No active TCP connection

[Giuseppe Larosa]

Hello Khairul,

>> remote host not responding

either the other device is not configured for this eBGP session, or you require

neighbor a.b.c.d ebgp-multihop 2

as the default IP TTL for eBGP open message is 1

if the latter is the case, also the other side needs the ebgp multihop statement.

and also neighbor update-source to specify your source address.

also the local address is 0.0.0.0 and this is not correct so you may need to provide a way to reach the eBGP endpoint, I would say this is the sign something is missing like routes to reach the eBGP endpoint

Hope to help

Giuseppe

[Mohd Khairul Nizam]

the other end is ISP. They said everthing is ready. 

this is my config. is it correct?

router bgp 65322
 no synchronization
 bgp log-neighbor-changes
 network 172.9.0.0
 network 172.19.0.0
 network 172.29.0.0
 network 172.49.0.0
 neighbor 58.139.93.113 remote-as 23736
 neighbor 58.139.93.113 ebgp-multihop 2
 no auto-summary

[Giuseppe Larosa]

Hello Khairul,

can you post

sh ip route 58.139.93.113

you need a static route if the eBGP endpoint is not directly connected

also you need to present yourself with the expected IP address (neighbor update-source command)

but the first thing is to understand if the eBGP session is multihop or single hop

Hope to help

Giuseppe

[Mohd Khairul Nizam]

rtr_klcc#sh ip route  58.139.93.113
Routing entry for 58.139.93.112/30
  Known via "connected", distance 0, metric 0 (connected, via interface)
  Routing Descriptor Blocks:
  * directly connected, via Ethernet0/0
      Route metric is 0, traffic share count is 1

rtr_klcc#
rtr_klcc#sh ip route
Codes: C - connected, S - static, I - IGRP, 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, E - EGP
       i - IS-IS, 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

Gateway of last resort is not set

     58.0.0.0/30 is subnetted, 1 subnets
C       58.139.93.112 is directly connected, Ethernet0/0
rtr_klcc#

i dont know if the ebgp is single or multihop

[Giuseppe Larosa]

Hello Khairul,

it is is single hop because the remote end is directly connected you don't need any additional command just the 

neighbor 58.139.93.113 remote-as 23736

should be fine

now the strange thing is that your local address should be 58.139.93.114 and not 0.0.0.0 in the debug output

Can you ping the ISP side 58.139.93.113?

post output of the ping

and show ip arp 58.139.93.113

Hope to help

Giuseppe

[Mohd Khairul Nizam]

i remove neighbor 58.139.93.113 ebgp-multihop 2

also see below:

rtr_klcc#ping 58.139.93.113

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 58.139.93.113, timeout is 2 seconds:
.....
Success rate is 0 percent (0/5)
rtr_klcc#

rtr_klcc#show ip arp 58.139.93.113
Protocol  Address          Age (min)  Hardware Addr   Type   Interface
Internet  58.139.93.113           0   Incomplete      ARPA
rtr_klcc#

[Giuseppe Larosa]

Hello Khairul,

there is no connectivity with the ISP device, in fact the ARP entry is not complete (no MAC address is shown ). This is really meaningful.

verify with the ISP the basic connectivity

Hope to help

Giuseppe

[Mohd Khairul Nizam]

Ok, thanks for the help

will check with the isp,

will rated your answer