Problems with BGP Next Hop Self

From: Raj Bahad (raj.bahad@xxxxxxxxxxxxxx)
Date: Tue Jul 30 2002 - 13:01:02 GMT-3


   
Hi group,

I'm having trouble with the following scenario:

R2--------R1
           |
           |
           R3

R1 & R2 are in the same AS (100) and R3 is in AS 300. Essentially, when I
include the link between R1 - R3 in the IGP, R2 has no problems reaching all
networks on R3. However, if I remove this option and use a "next hop self"
command pointing to R2, this also is fine. The problem is when R3 tries to
ping networks on R1...because R1 does not know of the link (192.168.0.0)
network via its IGP, it is unable to reply to pings. This is because the
packet leaving R3 has its serial interface (192.168.0.0) as the source
address. Using extended pings (specifying loopback as source) R3 has full
reachability with R1.

Is there a way I can get R1 to respond to pings coming from R3 (serial
interface), without R1 including the R1 - R3 subnet in its IGP?

The config for all three routers has been listed below:

R1#sh run

hostname R1
!
interface Loopback0
 ip address 10.10.10.1 255.255.255.255
!
interface Ethernet0
 no ip address
!
interface Serial0
 ip address 172.16.20.1 255.255.255.252
 clockrate 125000
!
interface Serial1
 ip address 192.168.10.1 255.255.255.252
 clockrate 125000
!
interface BRI0
 no ip address
 shutdown
!
router eigrp 10
 passive-interface Serial1
 network 10.0.0.0
 network 172.16.0.0
 no auto-summary
 no eigrp log-neighbor-changes
!
router bgp 100
 no synchronization
 bgp log-neighbor-changes
 network 10.10.10.1 mask 255.255.255.255
 network 172.16.20.0 mask 255.255.255.252
 neighbor 10.10.10.2 remote-as 100
 neighbor 10.10.10.2 update-source Loopback0
 neighbor 10.10.10.2 next-hop-self
 neighbor 192.168.10.2 remote-as 300
!

R2#sh run
Building configuration...
!
hostname R2
!
interface Loopback0
 ip address 10.10.10.2 255.255.255.255
!
interface Ethernet0
 no ip address
!
interface Serial0
 ip address 172.16.20.2 255.255.255.252
 no ip mroute-cache
!
interface Serial1
 no ip address
 shutdown
!
interface BRI0
 no ip address
 shutdown
!
router eigrp 10
 network 10.0.0.0
 network 172.16.0.0
 no auto-summary
 no eigrp log-neighbor-changes
!
router bgp 100
 no synchronization
 bgp log-neighbor-changes
 network 10.10.10.2 mask 255.255.255.255
 neighbor 10.10.10.1 remote-as 100
 neighbor 10.10.10.1 update-source Loopback0
!
ip classless

R3#sh run
Building configuration...
!
hostname R3
!
interface Loopback0
 ip address 10.10.10.3 255.255.255.255
!
interface Loopback1
 ip address 123.123.123.123 255.255.255.0
!
interface Loopback2
 ip address 111.111.1.111 255.255.255.0 secondary
 ip address 111.111.2.111 255.255.255.0 secondary
 ip address 111.111.3.111 255.255.255.0 secondary
 ip address 111.111.4.111 255.255.255.0 secondary
 ip address 111.111.5.111 255.255.255.0 secondary
 ip address 111.111.6.111 255.255.255.0 secondary
 ip address 111.111.7.111 255.255.255.0 secondary
 ip address 111.111.8.111 255.255.255.0 secondary
 ip address 111.111.9.111 255.255.255.0 secondary
 ip address 111.111.10.111 255.255.255.0 secondary
 ip address 111.111.0.111 255.255.255.0
!
interface Ethernet0
 no ip address
!
interface Serial0
 no ip address
 no ip mroute-cache
 shutdown
 no fair-queue
!
interface Serial1
 ip address 192.168.10.2 255.255.255.252
!
interface BRI0
 no ip address
 shutdown
!
router eigrp 10
 passive-interface Serial1
 network 10.0.0.0
 network 192.168.10.0
 no auto-summary
 no eigrp log-neighbor-changes
!
router bgp 300
 no synchronization
 bgp log-neighbor-changes
 network 10.10.10.3 mask 255.255.255.255
 network 111.111.0.0 mask 255.255.255.0
 network 111.111.1.0 mask 255.255.255.0
 network 111.111.2.0 mask 255.255.255.0
 network 111.111.3.0 mask 255.255.255.0
 network 111.111.4.0 mask 255.255.255.0
 network 111.111.5.0 mask 255.255.255.0
 network 111.111.6.0 mask 255.255.255.0
 network 111.111.7.0 mask 255.255.255.0
 network 111.111.8.0 mask 255.255.255.0
 network 111.111.9.0 mask 255.255.255.0
 network 111.111.10.0 mask 255.255.255.0
 network 123.123.123.0 mask 255.255.255.0
 neighbor 192.168.10.1 remote-as 100
 no auto-summary
!
ip classless

Regards,

Raj.



This archive was generated by hypermail 2.1.4 : Sat Sep 07 2002 - 19:36:49 GMT-3