IP address conflicts

Ted Mittelstaedt tedm at toybox.placo.com
Mon Sep 27 20:25:54 PDT 2004

> -----Original Message-----
> From: owner-freebsd-questions at freebsd.org
> [mailto:owner-freebsd-questions at freebsd.org]On Behalf Of russell
> Sent: Sunday, September 26, 2004 10:36 PM
> To: bsdfsse
> Cc: freebsd-questions at FreeBSD.ORG
> Subject: Re: IP address conflicts
> or use a tool like arpwatch that is specifically designed to let you
> know when MAC/IP relationships change on your network.

You don't even need to do that - any router on the network is going to log
the MAC address because they will see the arp change, as will the other

> you log the MAC addresses of all the fixed workstations in the school,
> then when one of them starts doing the wrong thing you know *exactly*
> where to go to nab the culprit.

How, exactly?  Do you think that he has a list of all MAC addresses on the
network and who is using them?

Getting the MAC address is not the problem.  Finding it on what is
a completely flat network is.  You need managed switches for this so you can
see what port the offending MAC address is on.

> If it's not one of the fixed
> workstations then you've got a bit more work to find the kiddie, but
> it's nothing insurmountable.

Unless of course the kiddies are using made up MAC addresses like


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