DNS / DHCP - Since the holidays - DNS all wrong !!! Scavenging not working

[burgemaster]

Can anyone please help. I thought we had DNS working perfectly, but after the 6 weeks holiday i have noticed that around 40% of the computer in DNS have the incorrect IP.

I have followed several guides and noticed that our outdated timestamped DNS entries arent being scavenged. I have set scavenging in the 3 places suggested:

The DNS server - "Automatic Scavenging of stale records" enabled and set to 7 days
The Zone - "Scavenge Stale Resource records" enabled, No-Refresh interval set to 3 days. Refresh interval set to 3 days.
DHCP has the Lease Duration set to 3 days.

I have DNS records with the dates of May 2011. I have tried to tell DNS to scavenge records now but i get the 2052 error.
I can only see one 2051 log of scavenging report from back in Jan 2011 and nothing has been touched since then.?

Can anyone please advice their working dates and times or suggest a solution for me?

Thanks in advance!

[burgemaster]

Is no-one prepared to share their No-Refresh/Refresh-Interval/DNS Scavenging age/DHCP lease durations with me

[Geoff]

Read through this article and double check your settings.

Don't be afraid of DNS Scavenging. Just be patient. - Microsoft Enterprise Networking Team - Site Home - TechNet Blogs

[burgemaster]

Cheers Geoff,
That was the main guide that I followed... I have just re-read and noticed that on one of the screenshots:
image_4.png

He has "Update Assosiated Pointer (PTR) Record" ticked for his DNS records.

Does everyone else have this enabled on each of there DNS records??

[Geoff]

He has "Update Assosiated Pointer (PTR) Record" ticked for his DNS records.

Does everyone else have this enabled on each of there DNS records??

That's only for equipment that doesn't do it itself (printers for example). However Windows 7 doesn't seem to do it either sometimes. This seems to be down to a client side setting. Have a read of this.

Windows 7 & Reverse Lookup DNS Registration | ADdict

[glennda]

My Leases are set to 8 hours. and DHCP is setup to register the DNS of each client when it is issued an address. and also delete the a and pointer records when the lease has expired.

to look at these options right click on the scope and open the properties then look at the DNS tab

[burgemaster]

AT LAST !!!!!!

Event Type: Information
Event Source: DNS
Event Category: None
Event ID: 2501
Time: 11:40:40
User: N/A
Computer: XX2
Description:
The DNS server has completed a scavenging cycle:
Visited Zones = 5,
Visited Nodes = 1155,
Scavenged Nodes = 642,
Scavenged Records = 721.
This cycle took 0 seconds.
The next scavenging cycle is scheduled to run in 168 hours.

[Geoff]

So, what was wrong?

[burgemaster]

It wasnt enabled on the actual DC itself, and then i guess i was being impatient!

image_12.png

[Edwardjr]

Just had this problem myself! Was right clicking on the DC and selecting the Set Aging but never noticed the option in the properties menu!

[RabbieBurns]

if my dhcp leases are 12 hours, what refresh intervals should I be using?

[Geoff]

Best practice is that the refresh interval should be set to half the lease length. So in your case 6 hours.

[PiqueABoo]

Best practice is that the refresh interval should be set to half the lease length.

Why are the MS defaults still DHCP:8 days, and 7 days for the refresh intervals though? I'm convinced both intervals should be smaller than the lease. Not sure about the scavenging interval here i.e. how frequently to scavenge DNS.

Personally I hate scavenging because it's a serious kludge, and at this kind of turnover might consider: a) Getting DHCP to register and delete all the DNS records, b) Do something else to clean out the dynamic-registered DNS records overnight (you can make clever scripts etc. to do that).

I'm also wondering how much of an effect this has on AD size: Does it get big (if so how much bigger) because there are lots and lots of deleted/tombstoned DNS records hanging around?