Default routes

EdTheLad

I've read RIP will automatically send default route information in updates,ive tryed this and it doesnt work.I have two routers connected running RIP,on routerA i create a default route as follows:
ip route 0.0.0.0 0.0.0.0 null0, i expect to see a default route in routerB pointing to routerA but it doesnt appear in the routing table.

Using the ip default-network works fine but i read that both these methods should work.Any ideas??

2lazybutsmart

if you use the ip route command to create a default network on a router that is running RIP, you won't see that default RIP injected route in the routing tables of the other routers running RIP.

The only command that has worked for me on that issue is ip default-network. Actually, Todd Lammle points it out that the ip default-network command will propogate the route to other IGPs whereas the other command won't.


Where have you read they both work?

2lbs

EdTheLad

Cisco Press - Routing TCP-IP Volume I.pdf by Jeff Doyle
Chapter 12

2lazybutsmart

I was starting to think that maybe it might work with EIGRP, but I just tried it and it didn't.

johnnynodough

It should be advertising default routes, try applying the IP classless command on the routers.

EdTheLad

IP classless is enabled by default in 12.0 and above.Im using 12.3
Ip classless is used to disable the classful reading of the routing table, i.e.
instead of the router matching the classful boundry of routes it will perform a longest route match, so its nothing to do with the actual advertising of the default route and more to do with how the router interprets the routing table.Hope you understand what i mean!
I also tryed this with EIGRP with no success, i'm thinking maybe it worked in the old IOS and this method has been phased out.Maybe the weekend i will try with an 11.x load.
Cheers guys.

johnnynodough

instead of the router matching the classful boundry of routes it will perform a longest route match, so its nothing to do with the actual advertising of the default route and more to do with how the router interprets the routing table.Hope you understand what i mean!

Ahh yes, I see. Damn these words, so many to interpret wrong

darkuser

i have a way you can prove this.....
i've done it.
i have a linksys router
befsr41 to be exact.
you can set it to send and receive ripv2.
then take a 2500 router
place 1 ethernet on the 192.169.10/24 lan on the linksys.
then take a serial x-over and connect it to another 2500.
if all is set up correctly

viola ' a default route .....