using loopback for eigrp

[carl_townshend]

If I want to use my loopback interface to advertise for my eigrp, how do i do this, I have 2 routers both plugged in via ethernet on a 10.0.0.0 netork, loopbacks are configured with a 192.168.1.0 network, i have advertised both these in eigrp, but its using the 10.0.0.0 address to reach each other, how do i make it use the loopback addresses ?

[spremkumar]

Hi

I feel you want EIGRP to use ur loopback as ur router id while forming the neighborshipt with the peer if thats the case then u can make use of the following command under the eigrp routing process..

eigrp router-id loopbackip

This will force the router to use this ip as the router id while forming the neighborship with the peer router.

Also make sure that you have reachability for the loopback ips from both the routers...

yes ofcourse it will make use of the ethernet port which is the physical media to have the reachability to the loopback ip on the other router which is again a logical interface manually created to facilitate the routing process..

regds

[carl_townshend]

Is this the best practice then ? also I cant ping the loopback intface on each router, if each loopback ip is in the same subnet should they beable to ping each other ?

[spremkumar]

Hi

Its the best practice to have the loopback ids used as the router id and u need to configure them up as /32 (single host ip) on the routers instead of configuring them in same /24 subnet in different routers.

Else you can configure up a ip which belongs to different /24 subnet in each routers and advertise them accordingly in the routing process.

And as always you can advertise them as a single ip in ur EIGRP process using the mask option available in the latest ios codes.

regds

[carl_townshend]

hi

so your saying on say router A, add loopback 0 , ip address 192.168.1.1 255.255.255.255, and on router B use 192.168.1.2 255.255.255.255, even though its via ethernet, will this work ?, and will loopbacks not work if they are on the same ip subnet ?

[spremkumar]

Hi

Thts the general/better practice to keyin the loopback with /32 and make tht as the router id.

For advertising in the routing process too it will become handy a single simple host ip which has to be advertised instead of whole /24 block.

If its ospf in this case the highest ip being configured here will be used for the DR/BDR election process.

regds