Why have workstation IP addresses have changed since new server installation?

This is pretty cut and dry:

We recently replaced one of our servers and since that time, people's ip addresses have changed from the 172.16.5 network to the 162.16.1 network.  I am no longer able to connect remotely to the workstations in my domain without their new IP address.  Name resolution no longer works.

I set a few workstations to Static IP to see if I could regain name resolution, and was able to. I would just prefer to be using DCHP on the 172.16.5 network. What do you suppose is set up incorrectly? Thanks.
johnnymac08Asked:
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craigothyCommented:
Is there a possibility that your old server was providing DHCP for 172.16.5.x and your new server is not configured the same way?
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pamikenCommented:
did you install a dhcp server on the new server you setup???
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DocCan11Commented:
If all your clients now have a different IP address and are using DHCP the problem is one of two.. FIrst someone has put a DHCP server on your network and it is giving out the worng IP's.. or two someone has changed your scope on your DHCP server.. The easiest way to find out is on one of the new clients type ipconfig /all from the command prompt and look for the IP address of the DHCP server that gave them the address.. this is your culprit
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ocon827679Commented:
Agree with DOC.  Go shoot the admin that put up a dhcp server and had the priviledges (Enterprise Admin) to authorize the server.  (Or do you think that there is an applicance that someone configured on the network giving out the addresses)  Of course, anyone can put up an NT 4 server and load DHCP Server.  That would do it also.

OK - don't shoot him, usually a threat of bodily harm will suffice!
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johnnymac08Author Commented:
Yes. DHCP server has been installed on new server.
Yes, looking at the old server, DNS reverse lookup zones look different.  Also, the old server is still hooked up.   I think the issue is with the scope on the DHCP server.  A colleague who helped set this up is coming out now. Thanks  
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johnnymac08Author Commented:
The scope had changed, and for some reason the old 172.16.5 entires were screwing things up.  I manually removed the 172.16.5 entries and now am using the 172.16.1. network. Name resolution is back... thanks all.
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