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New Member

Cat 5505 - unknown vlans and 00-00-00-00-00-00 MAC addresses

A "show cam dy x/y" lists many (about 40) different vlans with 00-00-00-00-00-00 MAC addresses. I am running 5.5(18) on a Sup2g with vtp. The ports are assigned to vlan52 (which is correct). MAC addresses on vlan52 are valid and vlan52 is part of the vtp domain.

All of the broadcast MACs are on vlans that are not in the vtp domain. This is true even on ports that are not connected. With ports that are connected, if there is only one valid MAC address, portfast is enabled. On ports with multiple valid MAC addresses, portfast is disabled. Every port lists the same number of broadcast MAC addresses and vlans. The only noticable difference is with the number of valid MAC addresses.

I am running this same version of CatOS on the same model of supervisor elsewhere without this listing.

My guess is that some other uplinked switch is introducing vlans, but was wondering if anyone has seen this before and knows why all these vlans are being listed on every port? I was thinking that it could be a spanning tree problem which is why I verified that portfast was disabled on every port with a hub or switch connected.


New Member

Re: Cat 5505 - unknown vlans and 00-00-00-00-00-00 MAC addresses

It seems that clearing that dynamic CAM table has removed all the excess entries. So far they haven't come back. I'm still curious as to what would have caused them to be there in the first place....