We had a problem yesterday where one of our DHCP servers had a scope run out of IP addresses. We expanded the scope's range of IP addresses only to find out that it impinged on the 2nd DHCP server's scope, that still had IP addresses available for lease.
Let's say original was:
DHCP SERVER 1 = 10.10.8.50-150/24 DHCP SERVER 2 = 10.10.8.151-250/24
and the change was:
DHCP SERVER 1 = 10.10.8.50-200/24 DHCP SERVER 2 = 10.10.8.151-250/24
Why the clients didn't get told "go to DHCP SERVER 2 and try there", I don't know, since both DHCP servers are set in the routers for bootprelay.
So, long story short, I ended up SHORTENING the scope of DHCP SERVER 2.
DHCP SERVER 1 = 10.10.8.50-200/24 DHCP SERVER 2 = 10.10.8.201-250/24
The problem now is that some of the clients that had a lease before the problem are now refusing to get an IP.
The DHCP server logs show similar to:
> 11,07/22/11,08:23:32,Renew,10.10.8.170,DEVICE01.mydomain.local,XXXXXXXXXXX, > 11,07/22/11,08:23:38,Renew,10.10.8.170,DEVICE01.mydomain.local,XXXXXXXXXXX, > 11,07/22/11,08:23:43,Renew,10.10.8.170,DEVICE01.mydomain.local,XXXXXXXXXXX, > 11,07/22/11,08:23:48,Renew,10.10.8.170,DEVICE01.mydomain.local,XXXXXXXXXXX,
The client is reaching the DHCP server, and keeps asking for the same IP, AND the DHCP console shows this client getting this IP address...but the client ends up with a 169 private address instead.
The client continues over and over to get an IP and the logs show the above...but still the client won't get an IP.
I've tried rebooting the DHCP servers, rebooting the client, doing IPCONFIG /release and /renew, disabling the NIC and re-enabling the NIC, moving the PC to another part of the building, still no luck.
Any help is appreciated, before I end up calling Microsoft.