RIP default gateway

gleeb1234 · ‎02-04-2006

can someone please explane to me the consept of having a "Gateway of last resort" and still the default gateway is leared VIA RIP and not used by the one you administred...?

mahmoodmkl · ‎02-04-2006

Hi

Gateway of last resort means the router will forward u r traffic to that particular next hop address if it doesnt find the route for a particular destination in its routing table.

The rip learns about the networks which r advertise in its process so it is going to forward u r traffic to the known destinations as it is having the routes in its routing table.

Hope this helps

Mahmood

gleeb1234 · ‎02-05-2006

let me give you a scenerio.

i have defined a default network and i am sending a ping to an unknown network.

in addition to my gateway of last resort the RIP protocol has leared another default route threw somewhere in the network (i have no idia how he does that).

will he use my route or the leared route.

cro9uk · ‎02-05-2006

It will use the learned one. A gateway of last resort is exactly as it implies, a gateway of last resort to any network unknown to the router. Basically you are telling the router the next hop address to any unknown networks. You state that you are sending a ping to an unknown network, but if the network is learned through RIP then it's not unknown is it.

gleeb1234 · ‎02-06-2006

let me put it this way...

I exec the "sh ip route" command

gateway of last resort is 10.1.2.2 to network 0.0.0.0

bla....

R 0.0.0.0/0 [120/1] via 10.1.5.5, 00:00:00, serail0/1

now do you understand what i mean?

farhan.javed · ‎02-07-2006

Cud you plz show me the config of your RIP,

This is basically a learned route from a different router.

gleeb1234 · ‎02-07-2006

its a question i got from testking.

the question is simply a "sh ip route"

and what i wrote with some other routes... and then if you send a ping to x.x.x.x (unknows adress) how will the router prossess the ping.

olorunloba · ‎02-07-2006

Then I guess it is a typographical error. While different routing protocols can have the default route in their database pointing to different next-hops, only one is installed into the routing table. The choice of which is installed in the routing table is dependent on the Adimnistrative Distance of the protocol.

Therefore if you configure a static default route and RIP learns a default route also, the static route will be installed in the routing table by default. This is because by default, the AD of static routes is 1. However, if the AD of the static route is changed to 200, which is higher than the AD of RIP (120), the RIP default route will be installed in the routing table.

Forwarding of unknown addresses is based on the default route present in the routing table, irrespective of the source of the route.

However, if there are multiple default routes from the same routing protocol with the same metrics, these can be installed together into the routing table. The traffic is then load balanced across them.

Hope this helps