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MAC show fdb listing wrong port for a PC

MAC show fdb listing wrong port for a PC

New Contributor
I was looking for a device on a x460 switch by mac. I ran sh fdb . The return listed the machine's mac on our gateway port. I found the correct port by using the phone's mac which showed the correct port that the device was connected. The machine had no physical connection to the gateway port !!!! Anyone have any ideas how this could happen. The device port was a netlogin configured port.

Extreme Employee
We did resolve an issue with fdb learning with netlogin, see the following article:-

Just wanted to share a link on KB article which describes how to create and apply ACLs.

I would use ACL counters to see if switch receives packets from source mac *:13:d2:dd on port 4:4.
So if you can detect any packets with source mac *:13:d2:dd on port 4:4 then FDB entry will be legitimate.

You can use following policy as a template:
entry count_smac {
if {
ethernet-source-address ;
} then {
count smac_pkts;

It's not something you normally look for. I have never observed this before. I disconnected the machine and cleared the MAC table, then it disappeared. I watched it for a about 10 minutes prior and it was persistent.

I'm writing a macro to check switch ports from a dump to see if this happens frequently. It may happen a lot on Extreme switches and no one notices.