On completely random occasions, numerous servers on the network will
report in system.log that their IP address is being duplicated by
another
server with a specific MAC address. All the servers report the same
MAC
address as the "thief". It's the same Xserve every time, and this has
happened about 5 or 6 times now over the past year. The servers
are on the same Cisco 2950 as the culprit, and another 2950 that is
connected
to that switch also has servers that report duplicate IPs.
That second 2950 ... Does it report that that same MAC address (for
that same Xserve) owns those addresses or does it give a different
MAC address ?
The 2950's are configured in a fairly basic manner. They have SNMP
enabled,
spanning tree is off, cdp is off. There's no advanced
configurations on
any of the involved switches.
If I unplug the offending Xserve, that solves the issue. The other
servers
start working again.
There does not appear to be any suspicious programs running on the
server
in question. DHCP does not appear to be running.
Make absolutely certain, because what you describe is sort-of the job
of a DHCP server. Set one of your Macs to get its address using DHCP
and see if anything hands out an address in the range you're having
problems with.
So I really don't have any idea why this is happening.
But you've given a far better, more detailed and more useful, report
of the problem so we can start helping you solve it.
I've never seen it
before, many people whom I have asked have never seen it either. It
happens
randomly. Has anyone on the list seen this? Is there something I
should be
looking for? Could the NIC card be the problem?
Three most probable causes of the problem:
1) Something has DHCP service turned on that shouldn't do.
2) Defective NIC (Ethernet) card in that Xserve.
3) Defect in the firmware of one of your hubs or routers (broadcast
bit messed up).
Given that you wrote that unplugging the Xserve solves the problem,
I'm inclined to think (1) or (2).
Simon
--
Simon Slavin Fylde Building Room C11
Computing Development Officer 01524 65201 x 93569
Psychology Department
University of Lancaster
