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Trying to remove 2003 server

We have an old 2003 server that used to be our primary server.  It ran AD DC, DNS, DHCP, WINS, file shares, etc.  Over the years we have added additional 2008, 2008 R2, 2012, and 2012 R2 servers and moved services to those other servers.  We have finally migrated all services and all but one file share off it.  We would like to DCPROMO it to be a standard server as we need to raise the AD functional level for some software that requires it.  We have ensured that all services are pointed elsewhere, but we continue to get a large amount of authorization failures when it is demoted.  I have increased the LDAP weight so it should not be a primary server for lookups, but watching the TCP connections to it, it is still getting hammered by clients and servers for lookups.   We demoted it and when all the network authorization issues came up, we DCPROMOed the server and put AD back on and everything started working fine again.  I have done a lot of research and the only thing I can find is It turns out that weird things can happen when you mix Windows Server 2003 and Windows Server 2012 R2 domain controllers   But this article is not exactly what we are dealing with so I am hesitant to apply the hotfix.  It is only replicating to and from one other DC in Sites and Services.  It is not a GC, does run DNS.

Any thoughts on what we can do to figure out what is breaking when we demote this server?  We have multiple AD, DNS, DHCP, WINS, etc. servers in multiple locations so it shouldn't be dependent on this one server.  One suggestion was to reboot servers and clients when we remove it but that would be a major undertaking.  Should we add additional AD connections in sites and services so it replicates its changes out faster?
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Commented:
You need to move the FSMO role over from the 2003 server too.  But be careful, once seized do NOT reconnect the 2003 server again.

Author

Commented:
Sorry, forgot to mention that all FSMO roles were migrated to other servers.
Natty GregIn Theory (IT)
Commented:
then the dns in the workstation is still pointing to the old server
Distinguished Expert 2018
Commented:
Sounds like you didn't clean up DNS when you attempted to demote your server. Demoting does not clean up any of the service records in the AD zone, so clients and other servers querying for available DC's will still get those records, and depending on your site topologies and other factors, may be deciding that old server is still the rbest choice.

You need to drop the TTL on those records so they won't be cached long. Wait for the *old* TTL time to pass so clients that have already cached records won't have an issue. Demote. Then delete DNS records. That should fix the problem.
Leroy LuffHead of IT & DIgital
Commented:
I agree with Cliff - your issues are related to DNS.

Ontop of checking your dns records you will need to check static DNS settings on clients/servers - perhaps check dhcp settings to make sure aswell.

Author

Commented:
I checked clients and servers DNS settings for static entries that should be good now.  I lowered the TTL and will try to remove it tomorrow.   I didn't really think of DNS, guess I was expecting something more complicated!