Help! DHCP Problems Help!

[PJK]

Help!!!!!

I have several (erm about 100+) windows 2000 professional clients who are configured for DHCP, but none of these clients can get an IP. The server is windows 2000 server and is running perfectly (another 90 odd clients are connecting with no problems using Windows 9x).

I have AD and DNS installed and are working perfectly. AD and DNS are on the same server, DHCP is on a different server.

If I watch the DHCP statistics while trying to connect from a Windows 2000 pro client then it can see the client trying to connect (Request).

There are about 200 ip addresses available but only about 50 have been taken (by Windows 9x).

It works if I have reserved a Windows 2k pro client by their MAC address, but I couldn't do this for all my 2k pro clients.

Anyone!!!!!!!

[futuretech]

Have you tried releasing and renewing after the client is up and running to see if it grabs an ip then?
The following article might help, but it deals with clients that were on a different subnet. This could possibly be part of the problem as the W2K clients when not getting an address are allocated one from APIPA and hence could possibly be on a different subnet, so DHCP ignores them.
http://support.microsoft.com/default...;en-us;Q167014

[PJK]

Thanks futuretech. I took a look at your link but this DHCP server is the only one on a class B network (255.255.252.0). Ipconfig /release and then /renew does not work.

These w2k pro clients exist on this network and have not been moved.

Any other help, PLEASE!

[Matridom]

A few things to consider.. do you have any routers? cause if you do, they are generaly not set to forward Discover packets. DHCP work at layer2 and unless you have a relay agent, won't go past a router.

you may also want to setup a laptop with a packet sniffer and see what devices are blocking your discovers,

[PJK]

Thanks Matridom for your suggestion. There are routers on the network, but they are routing but to to class C networks (255.255.255.0).

I forgot to mention, that the DHCP server was working perfectly on a NT4 machine and when we moved it over (I mean moved as in I install DHCP as new on the w2k server), it just stopped giving IP's to w2k pro clients.

[futuretech]

Here is a couple of articles.
http://support.microsoft.com/default...;en-us;Q268833
http://support.microsoft.com/default...;en-us;Q197197

When you brought up the new server did you remove the old NT4 DHCP server, or shut it down?
If you can see the client requesting an IP then it would seem that the server is sending a refusal.
The articles deal with that scenario. If a client asks for an IP adddress and that client had an address from a different range, when they request an address the DHCP server ignores (refuses) the request because it is in a different range and the DHCP server assumes a different DHCP server is servicing those ranges.
Another thought is check managed servers and see if a record of the old server is showing on the new server. If it is remove it.