There are duplicate IP addresses, not duplicate MACs. And all the duplicate IP addresses come from the same MAC address, as if a single machine had suddenly all the IP addresses configured on the same interface. I don't see how this can be attributed to a L2 loop.
Firesox, what is this phantom MAC address? Thanks, Zsombor Tom Martin wrote: > > As far as the duplicate MACs go, it sounds like you have a > layer-2 loop. > Especially considering that all of your servers are > experiencing the > problem. When they ARP to verify that no other station has > their IP, > they see their own ARP and assume that another station is doing > the same > thing. > > Layer-2 Loops will also cause MACs to appear to be sourced from > different switches in the network. > > Is STP enabled everywhere? Mismatched channelling will also > cause the > same behavior. > > Firesox wrote: > > I have a bunch of 3500XL switches thruout my customer's lan. > > They are having a problem with unknown mac keep appearing and > disappearing > > from the network. > > > > I can trace the mac-address of the unknown station by "show > mac" from the > > swtich CLI. > > What's strange is that it appears at one switch, but a minute > later it > > appears in the different switch. > > > > what's even more strange is that all NT/2000 servers log > shows there is an > > IP conflict with this mac address. > > Of course, the servers IP function stops due to this > duplicate IP, but comes > > back in a few minutes. > > All the servers report the duplicate IP comes from the same > mac address. > > > > Has anyone seen this problem? > > > > Thanks > > **Please support GroupStudy by purchasing from the GroupStudy > Store: > > http://shop.groupstudy.com > > FAQ, list archives, and subscription info: > http://www.groupstudy.com/list/cisco.html > > Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=73904&t=73868 -------------------------------------------------- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
