DHCP deleted reservations?

We recently had a maintenance period where we shutdown our DHCP server for
5-6 hours. Upon bringing the server back up, we found that the DHCP server
lost a number of reserved IP addresses. This resulted in several machine
obtaining an incorrent dynamically assigned IP instead of the reserved IP.
We had to enter the reserved addresses again in order to get it fixed.

Why would the DHCP server do that? Is there something that I may have
missed? It almost seems like it lost the most recent changes and selectively
too.

Devin Leung wrote:
> We recently had a maintenance period where we shutdown our DHCP
> server for 5-6 hours. Upon bringing the server back up, we found
> that the DHCP server lost a number of reserved IP addresses. This
> resulted in several machine obtaining an incorrent dynamically
> assigned IP instead of the reserved IP. We had to enter the reserved
> addresses again in order to get it fixed.
>
> Why would the DHCP server do that? Is there something that I may have
> missed? It almost seems like it lost the most recent changes and
> selectively too.

This shouldn't have happened...
....but what did you do during this maintenance period? Had you merely
stopped the DHCP server? Any event log errors, any other problems?

Microsoft dhcp uses a jet database which in the past was prone to
corruption. You could check the event log and see if anything appears, also
check out this link http://support.microsoft.com/Default.aspx?kbid=173396
"Devin Leung" <(E-Mail Removed)> wrote in message
news:6BE28772-B70C-4C52-91EC-(E-Mail Removed)...
> We recently had a maintenance period where we shutdown our DHCP server for
> 5-6 hours. Upon bringing the server back up, we found that the DHCP
server
> lost a number of reserved IP addresses. This resulted in several machine
> obtaining an incorrent dynamically assigned IP instead of the reserved IP.
> We had to enter the reserved addresses again in order to get it fixed.
>
> Why would the DHCP server do that? Is there something that I may have
> missed? It almost seems like it lost the most recent changes and
selectively
> too.

"Lanwench [MVP - Exchange]" wrote:

> Devin Leung wrote:
> > We recently had a maintenance period where we shutdown our DHCP
> > server for 5-6 hours. Upon bringing the server back up, we found
> > that the DHCP server lost a number of reserved IP addresses. This
> > resulted in several machine obtaining an incorrent dynamically
> > assigned IP instead of the reserved IP. We had to enter the reserved
> > addresses again in order to get it fixed.
> >
> > Why would the DHCP server do that? Is there something that I may have
> > missed? It almost seems like it lost the most recent changes and
> > selectively too.
>
> This shouldn't have happened...
> ....but what did you do during this maintenance period? Had you merely
> stopped the DHCP server? Any event log errors, any other problems?
>
>
>

We powered off the DHCP server and physically moved it to a different
network switch.

In the event log there is this entry.

Event Type: Error
Event Source: DhcpServer
Event Category: None
Event ID: 1065
Date: 1/7/2005
Time: 10:42:56 PM
User: N/A
Computer:
Description:
There were some orphaned entries deleted in the configuration due to the
deletion of a class or an option definition. Please recheck the server
configuration.

In the corresponding DHCP log file, I can see that it started a Database
Cleanup and removed several IP entries. As far as I can tell, the DHCP
database was not corrupted.