Seems if you let the DHCP lease time expire on the machine that is SUPPOSED to have that IP address, ie. not the rogue machine, then you could reconnect and "potentially" get a different IP address (once your DHCP lease has expired). The date on which your DHCP lease expires would indicate the length of time a temporary solution would have to be put in place, a different MAC address assigned on the NIC, a router between the network and computer, etc.
I say potentially get a different IP address because in theory it sounds like the rogue machine is not correctly identifying itself on the network and as Doug says the DHCP server does not properly skip over that IP address during assignment. But once your DHCP lease expires, ANY new DHCP lease seems like it would be at risk of conflicting with this rogue box, so maybe once it expires just connect and old machine and see if you get the IP in question, if you do, reconnect your other box you're having issues with and you should have a new IP.
All of the above are things you could try yourself, of course the best *supported* method would be to get with the network folks and track down this other box.
Christopher M. Harper
MANAGER OF INFORMATION TECHNOLOGY
University Relations, Michigan State University
401 Olds Hall, East Lansing, MI 48824-1047
Email: [log in to unmask] / Direct: (517) 355-9980
Web: http://ur.msu.edu / Cell: (517) 290-5496
From: MSU Network Administrators Group [mailto:[log in to unmask]] On Behalf Of Kwiatkowski, Nicholas
Sent: Friday, February 27, 2009 8:00 AM
To: [log in to unmask]
Subject: Re: [MSUNAG] How to force a new IP address from DHCP?
Dak,
If you plan to use an IP address in the static range, you MUST let the ATS Network Management group know. A simple email to [log in to unmask] will sufficie. Believe it or not, they actually do track these things and coordinate IP addresses across departments and the University. An IP address that you randomly grab might be the address of my firewall or device that is temporarly unavailable, causing the same issue you were trying to avoid. Just as Jeff Utter said earlier -- just because something dosen't respond it ICMP requests (PING), dosen't mean that it's not out there.
-Nick Kwiatkowski
MSU Telecom Systems
________________________________________
From: MSU Network Administrators Group on behalf of Aldrich, Dak
Sent: Thu 2/26/2009 8:53 PM
To: [log in to unmask]
Subject: Re: [MSUNAG] How to force a new IP address from DHCP?
Ok. Here's what I'd do in the short term...
I don't know about anyone else, but my two buildings each have two IP
ranges. One, the 35.10.89.x, is the DHCP address range. 35.8.225.x is my
static ip range. I'd find an ip in the static range that is not in use, and
set the machine that can't connect to one of those for now, until you find
the rogue machine. That way, you are not creating another possible conflict
by setting a DHCP address as static.
Just my 2 cents...
-dak
On 2/26/09 4:06 PM, "David McFarlane" <[log in to unmask]> wrote:
> How can we force the campus DHCP server to assign a new dynamic IP
> address to a machine, instead of just re-assigning it its latest IP address?
>
> We seem to have rogue machine in the building set up to use an IP in
> the dynamic range as its static IP address, so when DHCP gives that
> address to our machine we get an IP conflict error. We have tried
> releasing & renewing the IP, but that just gets us back the same IP
> address that has the confilict. We also tried unregistering the
> machine from the campus DHCP server, then re-registering it, with the
> same result.
>
> So we want to tell the DHCP server, "Please give us a dynamic IP that
> is different from the one we already have, thanks." How do we do that?
>
> Thanks,
> -- dkm
********************
* dak aldrich
* network admin
* college of music, msu
* [log in to unmask]
* 517.432.5045
* comit.music.msu.edu
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