Update-source question

[BillyBobKnob]

in BGP why would you use a FastEthernet port with update-source? I thought you always used loopback.

[Harold Ritter]

It doesn't make much sense to use update-source if you specify the physical interface address as the source address and you are correct this command is generally used along with the loopaback interface.

Hope this helps,

[BillyBobKnob]

This is what I think, but I have seen update-source FastEthernet0/0 used in this CCIE Practice Lab

http://www.informit.com/articles/article.asp?p=330806&seqNum=33&rl=1

any idea why ??

[Harold Ritter]

It can be useful if you have multiple leading to the neighbor address. It would then be required to use the update-source command to make sure that only one address will be used as the source of the bgp session. The reason not to use the loopback in this case might be that the loopback is not a public ip address and the session is ebgp.

Hope this helps,