I have a network with 2 x Windows 2008 R2 SP1 Servers with AD replication between them. I removed 2 x Windows 2000 DC's from the network (one of which was a print server) and moved the printers to one of the 2008 servers. I created a CNAME Alias for the old server and modified the registry to DisableStrict Name Checking and Enable DnsOnWire.
I created two spn records on the new printserver:
setspn -A HOST/alias newserver
setspn -A HOST/alias.domin newserver
Everything works as expected. After some random time, both spn records disappear from the server and I can no longer access the printserver using the old computer name. If I recreate the above SPN's, then I can access the server using the old computer name and all of the printers that pointed to the old server work.
Any Ideas as to why the spn's are disappearing?