How to find out loopback IPs

Unanswered Question
Jan 31st, 2008

Dear all,

how to find out loopback ip of router which are connected back to back?

what is the purpose of loopback ip's?



I have this problem too.
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senthil_kumarpv Thu, 01/31/2008 - 23:40

Loopback ips are used for the Routing protocols which nevers goes down,it is always up since it is logical.we can use it in ospf , BGP etc.


Rick Morris Fri, 02/01/2008 - 07:18

To find the IP's of a loopback interface you can log in to it and run several different commands.

show ip interface brief

sh ip int brie

-This will give you all the interfaces on the router that are configured along with their IP address if set and their status, up/down

show running-config

sh ru

-This will give you a line by line visual of the entire contents configured in the router. This will take more disecting but you will find the info you are looking for this way too.

show interface

sh int

-This will give more detailed information about all interfaces on the router. You will need to disect the output to find the info you need here as well.

For the quick snapshot use the sh ip int bri command


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