This reminds me of a story I was told a while back that there was a batch of 3com NIC's that all went out with the same MAC from the factory. I never found out if that was a rumor/urban legend or the truth. Anyone know firsthand or have an article about that? -Scott -----Original Message----- From: Robert E. Seastrom [mailto:rs@seastrom.com] Sent: Friday, September 05, 2008 10:33 AM To: nanog@nanog.org Subject: [Fwd:] Nvidia NICs with duplicate mac addresses Forwarded to NANOG in the interests of wider awareness... having been there and torn out my already scarce hair, duplicate MAC addresses can really mess up your day... --- Just when you thought this couldn't happen any more... Copying from a different email list... mac address 04:4b:80:80:80:03, was showing up in multiple places across the network. I googled the mac address and discovered that other people are having the same issue with this mac address. Below are some links describing the problem: http://forums.nvidia.com/index.php?showtopic=22148 http://www.nvnews.net/vbulletin/archive/index.php/t-73469.html I just wanted everyone to know about this problem in case you run across similar slow "connectivity" issues. I believe the network card is made by NVIDIA.