win2k3 DHCP and DNS

[shakamon]

Have a setup where server is doling out duplicate IP's in my Active Directory environment. I walked into this setup and did not originally set this up.

Typically, the old DNS A records still remain that were originally updated by DHCP. So when we look in DNS, we see duplicate IP's to diff hosts.

On DHCP server:
- its set to dynamically update DNS A and PTR when requested by client and discarded when lease is deleted.

-DHCP Lease duration has been changed to only 1 day.

- changed conflict detection tries to 1 from 0

On DNS servers (there are 2):

- Zone aging\Scavenging changed to 1 day on particular foward lookup zone. (Not in the props of the actual DNS server)

-AD integrated updates

I really need to get this cleaned up. It looks like a lot of the default setting wer changed and I need to back peddle.

Only the dead fish follow the stream

 

[theravager]

Scavenging has to be set on a couple of places to actually work.

Check that the ownership of some of the old records aren't what is also causing the issue. Maybe worthwhile setting your dhcp lease times to a low setting and do a manual deletion of records on a friday night or something similar.

 

[ITPangaeaArchitect]

Where is DHCP running? If on a DC, this is by design, if on a UNIX/Linux/Sun system, this is also by design....there is a workaround...

If I remember right, there's a bug, that won;t be fixed, in DHCP where discarding DNS records for clients does not work as its supposed to.
However, the method that should be used here is the always update DNS setting..do not leave it up to the client..if you do, DNS records will never clean out.
The quam here, and also the reason for the by design explanation above, is because the DHCP server takes ownership of the DNS records, thereby making itself the owner of the DNS record and NOT the client system.

Try always update DNS and see if it does the trick. Its possible someone who didnt really know much about the technology set it up, in which case, you may be better off to wack the zone completely and start over with proper DHCP and DNS configs and see if the problem gets resolved.

-Brandon Wilson
MCSE00/03, MCSA:Messaging00, MCSA03, A+
Manager - Global AD Operations
ACS, Inc.

 

[lhuegele]

Having a lease time of 1 day just seems too quick. I would raise the lease time to 7 days and see if that helps your situation.

Good luck,

 

[ITPangaeaArchitect]

the lease time should be fine since the dhcp client service verifies and re-registers around every 1.5 hrs.

-Brandon Wilson
MCSE00/03, MCSA:Messaging00, MCSA03, A+