DHCP not issuing spare addresses

[parsonjack]

we have 1063 addresses in our single scope, which has been working fine for some time, serving only around 400 clients. recently though we've had problems getting ip's for new clients, although renewals seem to be be working fine. the scope kept dishing out the last address xxx.xxx.xxx.255 which we know should not have been in scope and is now reserved from issue, but although there should be masses of ip's available we can only get new machines to pick one up when another machine drops its lease. its like its run out of ip's - but we know there should be loads available. any ideas????

 

[Serbtastic]

What subnet mask did you define for your scope?

 

[parsonjack]

subnet mask is 255.255.252.0 which gives a contiguous group of 1024 (not 1064..doh) ip's in xxx.xxx.48.0 - xxx.xxx.51.255.

 

[aznluvsmc]

Does the DHCP server actually say it has those IP's available? Check the IP lease status of the scope and it will tell you how many IPs it has free.

Steven S.
MCSA
A+, Network+, Server+, i-Net+

 

[GlenJohnson]

recently though we've had problems getting ip's for new clients, although renewals seem to be be working fine. the scope kept dishing out the last address

What has changed? Is there anything in the event logs?

Glen A. Johnson
If you're from Northern Illinois/Southern Wisconsin check out Tek-Tips in Chicago, Illinois Forum.

TTinChicago

http://www.johnsoncomputers.us

 

[ricpinto]

Maybe DHCP database is corrupted. Try and restore it from your back-up(when DHCP is working fine).

http://www.microsoft.com/resources/.../server/reskit/en-us/tcpip/part2/tcpch04.mspx

 

[parsonjack]

DHCP Manager shows 40% Active/Excluded and 59% Available. The first subnet in the range (255 addresses) are Excluded for use as Statics - which still leaves me with 750+ ip's for 400 clients.

There is nothing obvious in the Event Logs but there are a number of JET Logging/Recovery events that seem to coincide with the reboots we have done in pursuit of the issue. I also had problems when trying to add an Exclusion for a single address in that although I could add the address as an Exclusion hitting OK just hung the Manager, stopped the DHCP Server service and generated a Dr Watson error.

I'm beginning to think the db is screwed....any other opinions?

 

[aznluvsmc]

Try compacting the DHCP database before you think about restoring it.

Steven S.
MCSA
A+, Network+, Server+, i-Net+

 

[parsonjack]

yup...tried compacting with jetpack.exe....no joy. weird thing just spotted is that the active leases include a couple of ip's from the Excluded range... gonna try gassing the current db, copying a clean system.mdb from the disk and then a Reconcile against active leases held in the Registry.