RIP w/ Unnumbered Interface Issue

jas2061461 · ‎11-13-2012

R6 - R7 via Serial link. R6 is installing updates from R7 in its R.T. R7 is receiving updates from R6 but not installing the routes in the RIP database or R.T. Any ideas what might be wrong?

R6:

version 1

timers basic 30 180 0 240

passive-interface Loopback99

network 192.168.1.0

network 192.168.2.0

default-metric 13

no auto-summary

no valid-update-source

interface Serial0/0

ip unnumbered Loopback99

ip rip send version 2

ip rip receive version 2

encapsulation ppp

interface Loopback99

ip address 192.168.2.5 255.255.255.252

end

R7:

version 2

no validate-update-source

timers basic 30 180 0 240

passive-interface default

no passive-interface FastEthernet0/0

no passive-interface Serial0/0

no passive-interface Serial0/1

network 10.0.0.0

network 192.168.1.0

network 192.168.2.0

no auto-summary

interface Serial0/0

ip address 192.168.2.2 255.255.255.252

encapsulation ppp

clock rate 64000

no fair-queue

R6 Debug:

*Mar 1 02:11:29.615: RIP: sending v2 update to 224.0.0.9 via Serial0/0 (192.168.2.5)

*Mar 1 02:11:29.615: RIP: build update entries

*Mar 1 02:11:29.615: 10.0.0.0/8 via 0.0.0.0, metric 3, tag 0

*Mar 1 02:11:29.615: 40.0.0.0/8 via 0.0.0.0, metric 13, tag 0

*Mar 1 02:11:29.615: 172.16.0.0/16 via 0.0.0.0, metric 2, tag 0

*Mar 1 02:11:29.615: 192.168.1.0/24 via 0.0.0.0, metric 1, tag 0

*Mar 1 02:11:29.619: 192.168.2.4/30 via 0.0.0.0, metric 1, tag 0

*Mar 1 02:13:35.919: RIP: received v2 update from 192.168.2.2 on Serial0/0

*Mar 1 02:13:35.919: 0.0.0.0/0 via 0.0.0.0 in 13 hops

*Mar 1 02:13:35.919: 2.2.2.2/32 via 0.0.0.0 in 3 hops

*Mar 1 02:13:35.919: 4.4.4.4/32 via 0.0.0.0 in 3 hops

*Mar 1 02:13:35.919: 10.0.0.0/24 via 0.0.0.0 in 3 hops

*Mar 1 02:13:35.919: 10.1.0.0/24 via 0.0.0.0 in 9 hops

*Mar 1 02:13:35.923: 10.2.0.0/24 via 0.0.0.0 in 4 hops

*Mar 1 02:13:35.923: 10.3.0.0/24 via 0.0.0.0 in 4 hops

*Mar 1 02:13:35.923: 10.4.0.0/24 via 0.0.0.0 in 3 hops

*Mar 1 02:13:35.923: 10.100.0.0/29 via 0.0.0.0 in 2 hops

*Mar 1 02:13:35.923: 10.100.0.8/30 via 0.0.0.0 in 2 hops

*Mar 1 02:13:35.923: 10.100.0.32/30 via 0.0.0.0 in 1 hops

*Mar 1 02:13:35.927: 10.100.0.34/32 via 0.0.0.0 in 1 hops

*Mar 1 02:13:35.927: 172.16.0.0/24 via 0.0.0.0 in 2 hops

R7 Debug:

*Mar 1 02:12:41.671: RIP: sending v2 update to 224.0.0.9 via Serial0/0 (192.168.2.2)

*Mar 1 02:12:41.671: RIP: build update entries

*Mar 1 02:12:41.671: 0.0.0.0/0 via 0.0.0.0, metric 13, tag 0

*Mar 1 02:12:41.671: 2.2.2.2/32 via 0.0.0.0, metric 3, tag 0

*Mar 1 02:12:41.671: 4.4.4.4/32 via 0.0.0.0, metric 3, tag 0

*Mar 1 02:12:41.671: 10.0.0.0/24 via 0.0.0.0, metric 3, tag 0

*Mar 1 02:12:41.671: 10.1.0.0/24 via 0.0.0.0, metric 9, tag 0

*Mar 1 02:12:41.675: 10.2.0.0/24 via 0.0.0.0, metric 4, tag 0

*Mar 1 02:12:41.675: 10.3.0.0/24 via 0.0.0.0, metric 4, tag 0

*Mar 1 02:12:41.675: 10.4.0.0/24 via 0.0.0.0, metric 3, tag 0

*Mar 1 02:12:41.675: 10.100.0.0/29 via 0.0.0.0, metric 2, tag 0

*Mar 1 02:12:41.675: 10.100.0.8/30 via 0.0.0.0, metric 2, tag 0

*Mar 1 02:12:41.675: 10.100.0.32/30 via 0.0.0.0, metric 1, tag 0

*Mar 1 02:12:41.679: 10.100.0.34/32 via 0.0.0.0, metric 1, tag 0

*Mar 1 02:12:41.679: 172.16.0.0/24 via 0.0.0.0, metric 2, tag 0

*Mar 1 02:12:41.679: 172.16.2.0/24 via 0.0.0.0, metric 3, tag 0

*Mar 1 02:12:41.679: 172.16.3.0/24 via 0.0.0.0, metric 3, tag 0

*Mar 1 02:12:41.679: 172.16.4.0/24 via 0.0.0.0, metric 2, tag 0

*Mar 1 02:12:41.679: 172.16.5.0/24 via 0.0.0.0, metric 3, tag 0

*Mar 1 02:14:58.139: RIP: received v2 update from 192.168.2.5 on Serial0/0

*Mar 1 02:14:58.139: 10.0.0.0/8 via 0.0.0.0 in 3 hops

*Mar 1 02:14:58.139: 40.0.0.0/8 via 0.0.0.0 in 13 hops

*Mar 1 02:14:58.139: 172.16.0.0/16 via 0.0.0.0 in 2 hops

*Mar 1 02:14:58.139: 192.168.1.0/24 via 0.0.0.0 in 1 hops

*Mar 1 02:14:58.139: 192.168.2.4/30 via 0.0.0.0 in 1 hops

Does anyone know why R6 is installing the routes in its routing table, but R7 is not? I have looked through several (reference) guides and havn't seen anything address this issue. R7 is not installing any routes via R6 in its databse. I tried using the neighbor commands on both routers, but still no luck. R7 CAN ping 192.168.2.5 - the next-hop ip used to reach R6's networks. I am assuming the issue is with the unnumbered interface w/ RIP, but I see no errors in the debug.

John Blakley · ‎11-13-2012

Do you have a diagram? The p2p connection that you're showing above isn't on the same network, so I'm assuming that you have something in between if you can ping them. 192.168.2.0/30 isn't on the same network as 192.168.2.4/30, but you said that you can ping between the 2.

HTH, John *** Please rate all useful posts ***

jas2061461 · ‎11-13-2012

http://www.cisco.com/en/US/tech/tk648/tk362/technologies_tech_note09186a0080094e8d.shtml

Based on the documentation's example, an unnumbered interface can reference an IP address that is on a different subnet, yet still communicate between an adjacent router and exchange updates. The only portion of the diagram that I am having issues with is the communication between R6 and R7. These links are directly connected. To make tshooting easier, I shutdown all interfaces besides R6/R7's Serial 0/0.

The topology is R6 ---- R7. R6's unnumbered has 192.168.2.5/30 and R7 has 192.168.2.2/30. IE Different subnets.R6 is redistributing a 40.0.0.0/8 route w/ a metric of 13. R7 is using "default-information originate" to create a quad zero route w/ a metric of 13. R6 has installed the 0.0.0.0 to R7 via 192.168.2.2, yet R7 has not installed the 40.0.0.0/8.

R7's debug of rip events:

*Mar 1 00:02:47.919: RIP: received v2 update from 192.168.2.5 on Serial0/0

*Mar 1 00:02:47.919: 40.0.0.0/8 via 0.0.0.0 in 13 hops

*Mar 1 00:02:47.919: 192.168.2.4/30 via 0.0.0.0 in 1 hops

*Mar 1 00:04:19.455: RIP: sending v2 update to 224.0.0.9 via Serial0/0 (192.168.2.2)

*Mar 1 00:04:19.455: RIP: build update entries

R7 is not even placing the 40.0.0.0 in its database and therefore not being installed in the R.T.:

R7(config-if)#do sh ip rip da

0.0.0.0/0 auto-summary

0.0.0.0/0 redistributed

[13] via 0.0.0.0,

192.168.2.0/24 auto-summary

192.168.2.0/30 directly connected, Serial0/0

192.168.2.5/32 directly connected, Serial0/0

R7 is not using validate-update-source. IE There is no disregarding of those routes.

After changing R6 to be on the same subnet, changes were made on the loopback, R7 is still not installing the route:

R6#sh ip int s0/0

Serial0/0 is up, line protocol is up

Interface is unnumbered. Using address of Loopback99 (192.168.2.1)

R6#sh ip int lo99

Loopback99 is up, line protocol is up

Internet address is 192.168.2.1/30

R7#

*Mar 1 00:13:34.319: RIP: received v2 update from 192.168.2.1 on Serial0/0

*Mar 1 00:13:34.319: 40.0.0.0/8 via 0.0.0.0 in 13 hops

*Mar 1 00:13:34.319: 192.168.2.0/30 via 0.0.0.0 in 1 hops

R7#show ip route 40.0.0.0

% Network not in table

It appears to be an issue with RIP and unnumbered interfaces. Does anyone recognize an issue, or know the circumstances which RIP must apply to be compatible with an Unnumbered interface?

jas2061461 · ‎11-13-2012

Darnit! Found I was deny anything learned by R6. I didn't post the filtering, because I thought there wasn't an issue with it An hour of tshooting "down the drain"...guess I learned a lot more than I thought though...lol.

Answer:

R7:

router rip

distribute-list prefix INBOUND_FILTER gateway GATEWAY in

ip prefix-list INBOUND_FILTER seq 5 permit 0.0.0.0/0 le 32

ip prefix-list GATEWAY seq 5 permit 10.100.0.34/32

ip prefix-list GATEWAY seq 10 permit 192.168.1.1/32

ip prefix-list GATEWAY seq 15 deny 0.0.0.0/0 le 32

Richard Burts · ‎11-13-2012

Thanks for posting back to the forum to tell us that you found the problem and what the problem was. This is very helpful.

You may think that you had an hour of troubleshooting down the drain. But you learned a valuable lesson and it seems to me that the hour was in fact productive time.

HTH

Rick

HTH

Rick