Tuesday, January 22, 2008

DNS BACKUP



Question:

I have two DNS servers, one is a primary and the other is a secondary. Primary is AD integrated and a DC. Randomly and at random intervals things just up and disappear from the DNS records, even if I manually
input them into the records. I can't seem to figure out why. All servers are Win2k3 Any and all help is appreciated.

Answer:

I agree, your dilemma might be related to scavenging turned on from one of the DC's. I have seen very similar issue in a large enterprise environment where replication is a problem (KCC) and a DC which has scavenging turned on
thinks some records are stale and decides to purge them and advertise the changes in multimaster replication AD ( integrated DNS).it is kind of chasing a cat tale.
Have a second look on the DNS servers for scavenging In my case finding out
the DC causing problem and turning scavenging off did the trick. So here is a nice hint, how to backup DNS ( Thanks to Joe Nagy AD Expert
for simple smart solution)


It might not be a bad idea to run a scheduled task a couple times a day on DC that a good DNS server. Using DNSCMD.

dnscnd /zoneexport SMTP25.org SMTP25.org.bak

This will create a copy of the zone with the filename SMTP25.org.bak in the windows\system32\dns directory. If someone blows away DNS or something happens with replication or
scavenging.....

  • Go into the DNS mmc on that DNS server. Convert the zone from Active Directory Integrated to Primary.
  • Stop the DNS service.
  • Go to the windows\system32\dns directory, delete the
  • SMTP25.org.dns file and THEN...
  • Rename the SMTP25.org.bak file that you've been exporting to
  • SMTP25.org.dns


Start the DNS service and you have fully restored DNS zone.

Now simply go back in to the DNS mmc and convert the zone from Primary to Active Directory Integrated and it will replicate the good DNS around to all the DCs/DNS servers.

Best Regards,

Oz ozugurlu


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