Lab Question

elderkai

Hey, guys. I'm reading the FLG and decided to just lab up a little classful live example. This is the design of it: http://i.imgur.com/J0dDx.png
I used the same numbers and configured RIP v1. However, in the updates sent by R1, it's noted as 10.0.0.0 and then R2 doesn't put it in it's RIP table because it already has a static route for 10.1.0.0 I suppose, but it still passes it along. R1 and R3 both have the information I'd expect, but R2 has no RIP table with the exact routes to the loopbacks. Can anyone clear this up?

reaper81

Can you post the config you are using?

By default RIPv1 will be enabled and auto summary will be used. RIPv1 has no concept of subnet masks so it can't send any netmask information to the routers receiving the updates. Also if auto summary is enabled then networks will be summarized to their major network when crossing a major network boundary such as 10.0.0.0 to 172.16.0.0.

Also worth to note with RIPv1 is that it won't send networks out with another netmask than the one used on the outgoing interface. The exception is a loopback with /32 where all the host bits will be set.

Say that you configure router R1 with Fa0/0 172.16.1.1/24 and a loopback with 172.16.11.1/24. Then you have router R2 with Fa0/0 172.16.1.2/26.
What mask will R1 loopback have on R2? It will use the mask of the incoming interface so R2 will have 172.16.11.0/26 in its routing table.

If you provide more information I could try to walk you through the process.