According to Apple Insider, Apple has removed the 10.6.5 update for Mac OS X Server. Users are reportedly seeing major issues with both Lightweight Directory Access Protocol (LDAP) and Domain Name System (DNS), as well as Mail services.
In my experience, LDAP is the most widely used service on OS X Server machines, as it is required for many other services to operate. Without LDAP working correctly, users cannot authenticate against the server to use other services. DNS isn’t as widely-used, but issues with this service can cause network-wide problems for users.
This isn’t the first time Snow Leopard Server updates have caused issues. At the beginning of this year, Apple shipped a second version of the 10.6.3 Server update due to issues with the original update.
Usually server admins aren’t the type to roll out brand new software, so hopefully these issues aren’t widespread. It seems like waiting is the name of the game right now.