Last night I installed some Windows Updates and rebooted all of our servers.
Shortly afterwards I noticed that I couldn't ping some of our servers.
I noticed that the Host (A) records in the Forward Lookup Zones for these servers had vanished. Once I did an ipconfiig/registerdns on the member servers the records recreated successfully.
Why would the records vanish? We do not have scavenging enabled.
Recently we installed two new DCs in to our domain, which are both DNS servers (AD integrated). These are both Windows Server 2008 machines. We have an existing 2003 DC with DNS, and changed all the member servers to point to the new 2008 DCs for their DNS. They used to point to the 2003 DC.