Question regarding DNS reverse lookup zones

Question

Hi guys,

I have the following question. We have internal AD DNS server, and internal non-AD non-Windows DHCP server for VPN. The DHCP provides a new IP when a computer connects to the VPN.

When I check our DNS, in a forward zone, there are no duplicates, at the same time but there are a lot of duplicates records in the reverse zone.

Unfortunately, I can't know when a computer will connect to a VPN.

the current settings are:

for the created reverse record - TTL 20 Minutes

for reverse record - Delete this record when it becomes stale is active

for forward record - Update associated pointer (PTR) record and Delete this record when it becomes stale are active

SOA by reverse zone

refresh interval 15 min

retry interval 15 min

expires after 1 day

TTL - 1 hour

Only aging/scavenging is not set cause I'm not sure what should be the interval for removal in order to get rid of all these duplicates.

In general, I was expecting that the computer account will update its records and remove obsolete one.

Thanks

Answer 1

Hello,

 

Thank you for posting in Q&A forum.

Here's some configuration we can try based on your scenario:

For Refresh Interval, we can set it as 1 day to avoid frequent refresh.

For Retry Interval, we can keep it same as refresh interval.

For Expires After, we can set the maximum time a record can exist (In your case 20 minutes).

After the configuration you can enable the Aging/Scavenging feature.

For further information, please kindly check below Microsoft Official Documentation:

REF: https://learn.microsoft.com/en-us/troubleshoot/windows-server/networking/dns-scavenging-setup

 

I hope the information above is helpful.

If you have any questions or concerns, please feel free to let us know.

 

Best regards，

Jill Zhou

 

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