I have about 80 Windows (both Windows 7 and XP) clients under 2 domain controllers (One primary and One secondary). Both Domain Controllers hold the same DNS Forward Lookup Zone for availability reasons. The 2 DC are placed in different places in the same city, having a 3 mbit connection (Leased Line) between them. After performing Windows Updates on the Win 7 Clients, 2 specific Clients are deleted from the dns zone, without a specific reason, while they are working, causing application problems. In order to solve the issue I have to ipconfig/register dns or reboot the client machine. This command solves the problem temporarily but the event happens again, sometimes after couple of minutes , sometimes after some days. I dont have Sites configured. I dont use Aging or scavenging. I have many other windows 7 clients that dont face this problem at all. Both DCs are Windows 2008 Server R2 updated with all Microsoft updates until Nov 2011. Sorry for my English.

Check you dhcp settings. enable " Always dynamically update DNS A and PTR records" http://technet.microsoft.com/en-us/library/cc787034(v=ws.10).aspx

I forgot to mention that I don't use DHCP at all, because of application and network (lots of subnets) issues. All clients use static addresses.

It could be Active Directory replication problem where the record got marked for deletion on one of the servers. Check the event viewer on the domain controller there must be something registered for that. Static records usually don't get removed from DNS with scavanging. You could have same IP address assigned to 2 or more clients, check for duplicate ip addresses in DNS console.

There are is not any ip assigned to 2 computers. I checked Event viewer but did not find anything, both client and server. But I haven't d o u bl e cheched it. I ll check it by tuesday. I think that finally, I will have to disjoin both clients from domain and re join them back.

create "A" record manually in DNS and set the security that only you can delete it.

Hi, If the issue persists after creating A record, I suggest posting in Server Forum below to check the issue from server side. Network Infrastructure Servers http://social.technet.microsoft.com/Forums/en-US/winserverNIS/threads Niki Han TechNet Community Support