Hi Sir,
The following two routers (R6 & R9) are configured to form an eBGP connection:
R6
--
!
interface Serial0/0
description *** Connection to R9 ***
ip address 150.50.69.1 255.255.255.252
!
router bgp 600
neighbor 150.50.9.99 remote-as 900
neighbor 150.50.9.99 ebgp-multihop 3
!
address-family ipv4
neighbor 150.50.9.99 activate
no auto-summary
no synchronization
exit-address-family
!
ip route 150.50.9.0 255.255.255.128 150.50.69.2
!
R9
--
!
interface Loopback0
ip address 150.50.9.99 255.255.255.255
!
interface Serial0/0
description *** Connection to R6 ***
ip address 150.50.69.2 255.255.255.252
!
router bgp 900
neighbor 150.50.69.1 remote-as 600
!
address-family ipv4
neighbor 150.50.69.1 activate
no auto-summary
no synchronization
exit-address-family
!
From the config, it looks like the eBGP connection won't come up because the command "neighbor 150.50.69.1 update-source lo0" is missing on R9. Surprisingly, the connection did come up, as follows:
R6#sh ip bgp ne 150.50.9.99
BGP neighbor is 150.50.9.99, remote AS 900, external link
BGP version 4, remote router ID 150.50.9.99
BGP state = Established, up for 01:20:08
<---Output omitted--->
Connection state is ESTAB, I/O status: 1, unread input bytes: 0
Connection is ECN Disabled
Local host: 150.50.69.1, Local port: 50619
Foreign host: 150.50.9.99, Foreign port: 179
R9#sh ip bgp nei 150.50.69.1
BGP neighbor is 150.50.69.1, remote AS 600, external link
BGP version 4, remote router ID 150.50.6.6
BGP state = Established, up for 01:13:56
<---Output omitted--->
Connection state is ESTAB, I/O status: 1, unread input bytes: 0
Connection is ECN Disabled
Local host: 150.50.9.99, Local port: 179
Foreign host: 150.50.69.1, Foreign port: 50619
Please advise. I'm a little confused.
Thank you.
B.Rgds,
Lim TS
