Duplicate MAC Address

[cuttressb]

I am getting duplicate MAC address messages when doing a capture on my switched network. The frames have the same source and destination MAC's and seem to be all address's starting with 00-04 and are printers. In the Hex data field all I see is link test. This seems to have just started and I cannot figure out what is causing it.

[konigl]

IBM and/or Lexmark printers, judging from the first part of the MAC addresses. (Would need the next two characters or octet to pin it down.) Can't tell you much more than that, yet. One of the networks I work on has lots of IBM and Lexmark printers, I'll take a look at it in the next day or two, see if they're having the same symptoms and just don't know it.

Have you tried calling the above companies' tech support lines or surfing their websites? They may have some buggy code on their LAN cards that needs upgrading.

Maybe someone else will respond in the meantime who's also seen this.

[cuttressb]

They are indeed Lexmark printers and I never noticed this problem on previous captures and am wondering if I have a problem with the ARP tables on one of my routers but the problem only seems to be on the Lexmark printers. We did enable the ports on our print server to user Xerox Xcounter ports for printing and I thought that was the problem but after changing the port back to standard TCP/IP printing the problem could still be seen on some of the devices.