Loopback Question

[sdawson35]

      I'll start by apologizing for a numpty like question !.

We have a 2821 router (voice), we have 1 nic configured as the active nic on network 172.30.xxx.xxx/24 and the other nic configured as standby, these in turn connect to our core switches with the ports configured as switchports and in vlan xxxx.

We have configured a loopback address on the router in network 172.30.yyy.yyy/32

This does not work, does the loopback address have to be in the same network range as the interfaces ?            

[John Blakley]

It doesn't need to be in the same range, but your devices that lead to it need to know how to get to it. For example, if you have RouterA and RouterB connected on 192.168.1.0/30

RouterA = 192.168.1.1

RouterB = 192.168.1.2

RouterA has a loopback addressed as 200.200.200.200/32. On RouterB, you'd need to either run a routing protocol with RouterA and RouterA advertises the 200.200.200.200/32 or you'd need a static route on RouterB like:

ip route 200.200.200.200 255.255.255.255 192.168.1.1

HTH,
John

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[roger jones]

I agree you should check your router is advertising the static route for the loop back ....

Regards

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