DNS Headache entries appearing by magic

[Stuart_C]

Today I had a rummage round my DNS and a bit of a tidy up. I deleted a load of records for old devices and generally felt happy. I would have been happier if the scavanging worked but that's a different story.

 

So I've just checked it. My forward lookup zone is fine. Correct number of PC's and correct IP's. My reverse lookup zones are a bit more odd... For example some entries have reappeared that I deleted earlier. These entries are for PC's that I have renamed/removed ages ago. The namse do not exist in DHCP or on the network yet they have just popped up. also some of my computers don't have reverse DNS entries. I just nipped onto one, ran ipconfig /registerdns and... nothing.

 

I've got 2 Win2k8 r2 servers replicating DNS between them. Any ideas where I should be looking to figure this out?

[pantscat]

Have you enabled scavenging at all levels? Server and zone level?

[pantscat]

Sorry - just re-read this and realised I've got the wrong end of the stick.

 

Have you setup a reverse lookup zone for your subnet properly? - e.g. under "Reverse Lookup Zones" does it say A.B.x.x subnet (or whatever your subnet is!)?

[Stuart_C]

Yep. There are some entries in there and they do match up. It's just that there are some missing and some random ones that keep appearing.

[pantscat]

Hmm. Do you use DHCP to update the A and PTR records? I've noticed that some clients just don't update their PTR records properly even though they're supposed to.

 

Not sure what to say about the random ones popping up - are you sure they aren't rogue devices on your network? (e.g can you ping them?)