ripv2 auto-summary issue

ehnde

This is probably a stupid problem to have, but I'm stuck. I have two routers, 1721-1 and 1721-2.

1721-1 router:
router rip
 version 2
 network 10.0.0.0
 no auto-summary

That is the running-config for 1721-1 (relevant to rip).

That is what it should be. On router 1721-2 I have network 10.0.1.0 with no auto-summary, but in 1721-2's running config I'm seeing

router rip
 version 2
 network 10.0.0.0
 no auto-summary

Why is the 10.0.1.0 network being summarized to 10.0.0.0 on 1721-2?

okplaya

Check the routing table with it on/off.

ehnde

okplaya wrote: »

Check the routing table with it on/off.

Like this?

1721-2#clear ip route 10.0.0.0
1721-2#show ip route
Codes: C - connected, S - static, 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
       i - IS-IS, su - IS-IS summary, 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

     172.17.0.0/30 is subnetted, 1 subnets
C       172.17.0.0 is directly connected, Serial0
     10.0.0.0/24 is subnetted, 1 subnets
C       10.0.1.0 is directly connected, FastEthernet0

ehnde

OK here's the problem:

1721-2#
*Mar  5 14:00:37.973: RIP: sending v2 update to 224.0.0.9 via FastEthernet0 (10.0.1.1)

fa0 is up/up with no keepalive, but it isn't connected to anything. I need the rip updates to go out serial 0 on both routers. How do I correct this?

APA

router rip
 version 2
 no auto-summary
 network [serial interface network]
 network 10.0.0.0
 passive-interface default
 no passive-interface serial0

You need to specify specify the networks that will be operating RIP as well. Otherwise RIP will not be enabled on those interfaces.

Ensure you configure passive-interface default to stop RIP messages being sent out the FastEthernet interface, then specify no passive-interface Serial0 to ensure that RIP messages are sent out this interface.

Verify RIP database is built and that you receive RIP routes correctly.

Also ensure you specify 'ip classless' to ensure the RIB acts in a classless state and not a legacy classful state....I don't know what code you are running but 1721s are some very old routers, so 'ip classless' may not be the default if your code is old as well.

ehnde

APA wrote: »

router rip
 version 2
 no auto-summary
 network [serial interface network]
 network 10.0.0.0
 passive-interface default
 no passive-interface serial0

You need to specify specify the networks that will be operating RIP as well. Otherwise RIP will not be enabled on those interfaces.

Ensure you configure passive-interface default to stop RIP messages being sent out the FastEthernet interface, then specify no passive-interface Serial0 to ensure that RIP messages are sent out this interface.

Verify RIP database is built and that you receive RIP routes correctly.

Also ensure you specify 'ip classless' to ensure the RIB acts in a classless state and not a legacy classful state....I don't know what code you are running but 1721s are some very old routers, so 'ip classless' may not be the default if your code is old as well.

Solved now, thank you. The trick to this was enabling rip on serial 0. I didn't realize I needed to add network 172.17.0.0 to enable the serial ports to send rip updates to each other.

I'm learning alot from just "winging it" (not following lab book) and figuring out why stuff isn't working. Doubt I'll forget this lesson!

networker050184

The network command in RIP always falls back to the classful form. It doesn't necessarily mean that the update will be summarized though.