Trunk to server - Unicast traffic

abartolomeu · ‎10-01-2008

Hi!

I have configured a trunk to a server that is using several vlans. Why is the server receiving unicast packets that are not for it?

Thanks,

Ana

Giuseppe Larosa · ‎10-01-2008

Hello Ana,

frames with an unknown unicast destination MAC address are treated like broadcast and sent out of all ports that are member of the vlan including trunk ports.

So you could see some temporary frames with a destination different then the server NIC MAC address.

Note2:

if the server uses virtualization like VMware it can be using other MAC addresses for the virtual machines: there is a specific OUI for vmware: 00:0C:29

I see this on many servers using vmware.

They appear with different source MAC addresses in different Vlans of the same trunk port.

Hope to help

Giuseppe

abartolomeu · ‎10-02-2008

Thanks for your help.