Duplicate DNS and Scavenging.

[linkazoid]

Hi,

 

We have issues with multiple duplicate DNS records, which in turn causes issues with AV deployment and SIMS deployments.

 

We have configured DHCP to register the addresses on behalf of the clients in hope that this would resolve the issue. Either this isn't working correctly or something else is causing us issues.

 

Before I open a support call with Microsoft, can anyone help to see where our issue are.

 

In DHCP we have the following enabled under the DNS properties tab.

• Enable DNS dymanic updates according to the settings below.
  
• Dyanically update DNS records only if requested by the DHCP clients.
  
• Discard A and PTR records when the lease is deleted.
  

 

Under the advanced tab - Credentials. We have the account details and password of the dhcp1 account we have created in AD. This is a member of Domain users.

 

DHCP server has been added to DNSUpdateProxy group.

DHCP leases are set to 4 days for every scope.

 

In DNS, under the Server name properties, scavenging seems to be set at 1 day for both DNS servers.

Looking at the zones though, the ageing is set to No-Refresh 32 hours and refresh to 64 hours.

 

Under the security tab for a DNS entry I would expect to to see dhcp1 listed but it isn't.

 

Any help would be appreciated to help resolve this for us. Before having to resort to Microsoft paid services.

 

Thanks,

[ITGURU]

I think it may have something to do with your DHCP lease times and DHCP Scavenging times.

I have DHCP Leases set for 30 days.

 

You should only have 1 DNS Server set for scavenging for AD Integrated Zones, and I have mine set for Refresh and No-refresh at 20 days.

 

Never had any issues with duplicate entries in DNS or 2 machines resolving to the same IP with the above set-up.

[linkazoid]

Thanks,

 

There's a reason why we have such a small lease time as we have a limited number of IP's available in a scope for our wireless clients.

[RowlandoGloom]

If you're using Windows Server DHCP, you can enable DNS Name protection on the scope.

 

This creates an entry for the first device with that name, the IP DHCP has given, plus another record matching some other info.

 

You'll then only get the host and 1 IP. The only time it can be a headache is if there are two, say phones, with the same name. It just means they're not registered in DNS

Edited August 21, 2015 by RowlandoGloom