I inherited a pair of Catalyst 4000s with about 100 devices connected to each. I'm slowly going through and naming all of the ports (by a combination of 'show cam dynamic' and a list of MAC & IP addresses I have for our system), and came across one rather strange thing.
sh port 4 | I 4/15 4/15 unknown-weird connected 1 normal a-full a-1Gb
10/100/1000 4/15 none none 4/15 disabled shutdown 0 0 1 disabled
122 4/15 0 - - - - - 4/15 Enabled 4/15 on on desired on 0 0 0
4/15 connected auto silent 292 0 4/15 connected - Enable No Change 4/15 - 0 0 0 0 4/15 0 0 0 0 0 0 0
So, something's connected to it at 1Gbit and has negotiated full duplex. But check this out:
sh cam dynamic 4/15
- = Static Entry. + = Permanent Entry. # = System Entry. R = Router Entry. X = Port Security Entry $ = Dot1x Security Entry
VLAN Dest MAC/Route Des [CoS] Destination Ports or VCs / [Protocol Type]
---- ------------------ -----
------------------------------------------- Total Matching CAM Entries Displayed =0
It's the only device (out of the 200 or so) that does NOT have a MAC address. How is that even possible? I can't pull out the cable and unplug the device in question, at least not yet..!
Chris