So many loopback addresses on one router

Routing & Switching IP Routing
1

Why so many loopback addresses on single router? What purpose will it solve?I

2

Hello Sarang

Loopback addresses are useful in various configurations of routers. These include:

  1. the use as a router ID for dynamic routing protocols such as EIGRP and OSPF
  2. the use as the location from which BGP peering takes place, especially when creating multiple links between routers
  3. for testing and diagnosis purposes

Loopbacks should only be created when necessary, if there’s no reason to have them, then there’s no reason to create them.

I hope this has been helpful!

Laz

3

I have loopback 0 interface with an IP Address of 1.1.1.1/32 on my Cisco 2811. IP logging source-interface is loopback 0. The IP subnet attached to the Gigabit Ethernet 0/1 interface with as 193.X.X.X. i want to resolve the loopback interface so the hostname shows in the logs instead of 1.1.1.1. Hope I explained what I’m trying to do correctly. I think my DNS entry may be the issue.

4

adding the following line to the configuration fixed the issue. The hostname appears at the beginning of the log message.

logging orgin-id hostname

5

Hello Donald

Thanks for sharing your solution with us, it is always helpful for all users of the forum when we post our troubleshooting successes!

Laz