Archive for category DNS

x64 Sagas: Trashed DNS and Active Directory

Just recovered an Active Directory domain that was hurting (busy weekend) . DNS was not pushing correctly between servers, AD replications stopped and Exchange went offline except for OWA access.

Problem was traced to a probably corrupted DNS cache file on the Exchange server, demoting and re-promoting the server did not help. Users were getting immediate rejections from the Exchange server as offline and attempts to create new email accounts would fail as being not reachable. When substituting a domain controller’s name for the exchange server entry in Create Account, the process would get further: the server would be replaced with the underlined (real) name of the Exchange server and the username would verify as underlined, and then fail for lack of connectivity, pretty clear proof that it was a DNS issue.

On top of that DNSMGR was acting funny and stopping netlogon and running netdiag /fix was not backfilling the zone correctly.

Bottom line was we changed the DNS instance to Slave and changed the other DC to allow transfers and forced a transfer of zones (deleted all cache files we could find first). We then reintegrated DNS with AD and tested. Email started flowing and the Exchange server once again knew his own name.

Why is this an x64 Saga? The Exchange server was 2007 which only runs on x64 and the <skepticism> only </skepticism> event that we can find is that the x32 AD utilities may have been run against the x64 install which is supposed to be bad. I am not going to put the customer through proving it by testing that theory in detail, one remaining issue is the dnsmgr app remains broken, we have to use the DNS snapin for MMC to see the zones.

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