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DHCP server lost contact with partner

Posted on 2014-01-15
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Last Modified: 2014-01-17
I configure 2 new domain controllers with DHCP and configure the associated fail-over partner.  Some time after that I changed the IP address of both servers.
Now both have lost contact with each other.
The event log reports the following:
Server has lost contact with the partner server. 192.168.15.24 for relationship pdc1-pdc2
I changed the IP from 15.24 and 15.25 to 15.18 and 15.19.

Do not see anywhere to update the IP address of the failover partner.

I am afraid to deconfigure the failover as the deconfigure tells me that it will delete all the scopes that are a part of the failover relationship.

Anyway to fix this without starting over?
Thanks
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Question by:kbettencourt
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6 Comments
 

Author Comment

by:kbettencourt
ID: 39784513
I may have found the answer.  In the GC 15.18 I searched for the 15.25 IP.  There were 3 entries for 15.25.  I changed then to 15.19 and it appears to be replicating normally.
When I add or delete a reservation in the GC 15.18 it replicates to 15.19.

However when I add a reservation in 15.19 it does not replicate to 15.18.  And the new reservation in 15.19 is deleted when I initiate replication from 15.18.

I also need to add that the registry in 15.19 did not have any entries to the old 15.24 address of the GC so I made no registry changes to it.  I do have it recorded where I made the 3 registry changes to the GC and can change it back if necessary.

It's a little confusing, but it appears to be behaving like the primary is replicating one way.  Is that normal or should it be the same regardless of which one has the new reservation?

Additionally, I have noticed that when I add a reservation and then delete it and then try to add the same one again it gives me:
"An error occurred while accessing the DHCP database.  Look at the DHCP event log for more information on this error."
The log does not have any related entries.

Does any of this make sense?
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Author Comment

by:kbettencourt
ID: 39784519
Also found this concerning the re-creation of a previously deleted reservation.
http://conormcginty.wordpress.com/2012/08/20/an-error-occurred-while-accessing-the-dhcp-database/

This may indicate that the error accessing the database may be unrelated to the changes I made in the registry.
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Accepted Solution

by:
Sikhumbuzo Ntsada earned 500 total points
ID: 39784535
Do "ipconfig /flushdns" then "ipconfig /registerdns"
After that do "dcdiag /fix"

dcdiag /test:dns

Test replication by typing "repadmin /showrepl"

You can create a backup of your DHCP scope and re-do it if continues to give you problems.
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Author Comment

by:kbettencourt
ID: 39784550
Tried to find the deleted reservation with "netsh dhcp server scope> show reservedip" but the list matched what was in the MMC.  So the reservation deleted in MMC was actually deleted.  There may still be some issue associated with the changes in the registry.
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Author Comment

by:kbettencourt
ID: 39786998
Thanks for the response.  All results from the two test passed.
I suppose I can rebuild the database, but like I said, I am afraid.  All our phones have reservations as well.
Will work with it a bit longer and will rebuild if there is no alternative.
Thanks
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Author Closing Comment

by:kbettencourt
ID: 39788962
Finally removed the second dhcp server and all is behaving normally.  Deleting the failover relationship only deletes the scope on the failover server.
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