Re: [MSUNAG] How to force a new IP address from DHCP?
You could also use something like nmap to give you the likely vendor of the rogue machine, so you had a good basis to work off of when it came to tracking them down, and then follow up with a more, um, personal method of troubleshooting. Remember, gloved hands help keep from leaving marks.
Seriously though, the DHCP server is pretty sticky – I believe that once you’ve registered a machine it will keep assigning that IP to the same machine for quite a while. I don’t know if unregistering the machine from dhcp.msu.edu and re-registering it will help. AFAIK, the period of “quite a while” is on the order of months.
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Jack Kramer
Computer Systems Specialist
University Relations, Michigan State University
517-884-1231
From: Al Puzzuoli <[log in to unmask]">[log in to unmask]>
Reply-To: Al Puzzuoli <[log in to unmask]">[log in to unmask]>
Date: Thu, 26 Feb 2009 19:19:51 -0500
To: <[log in to unmask]">[log in to unmask]>
Subject: Re: [MSUNAG] How to force a new IP address from DHCP?
How about this:
Bring up the machine in question, let it register and obtain the bad IP.
Shut down the machine without unregistering it.
Plug in a cheap Linksys router, or some similar box, connect the PC to
the router and rerun the DHCP registration. This should register the
MAC of the router and give it a different IP. Of course now, the PC
will be behind a NAT firewall, but I wouldn't think that should present
a problem in most scenarios.
Al Puzzuoli
Michigan State University
Information Technologist
http://www.rcpd.msu.edu
Resource Center for Persons with Disabilities
120 Bessey Hall East Lansing, MI 48824-1033
517-884-1915