CDP

[sgalarza]

Hello, 

When I do sho cdp neighbors, I get multiple devices showing up on the same port.  Any ideas on why this is happening?  I though maybe because it was a trunk port, but some of our other devices are access ports and show the same output from sho cdp neighbors.  Any help would be great.

Thanks

[Leo Laohoo]

It means the downstream device directly connected to this port is either a hub or a transparent switch.

[sgalarza]

The downstream device is not a hub and by transparent switch are you talking about VTP? Because we don't use vtp in our organization.  

[Leo Laohoo]

There are Layer 2 switches that act as a "transparent" switch (not VTP mode Transparent) where they will just pass whatever traffic from one port to another.

[sgalarza]

Ok, I was also told, because of that port being our AT&T circuit that it was showing all of our other locations. Thanks for the input.

P.S. The switch is a 3400 series, not sure if that means anything.

[Leo Laohoo]

because of that port being our AT&T circuit that it was showing all of our other locations.

Hold on ... What???  This port is to your WAN?  

This is one reason why it is highly recommended to DISABLE CDP on WAN links if the WAN link(s) do NOT belong to you.  

Alternatively, you can also use Secure CDP on the WAN link(s).