I have been getting the below error (excerpt from dcdiag /c) somewhat randomly on various servers throughout the week during the last month. A dc reboot clears this up, but it;s starting to get really annoying. This error is resulting in replication issues that if left unchecked can seriously wreak havoc on our domain.
Directory Server Diagnosis Performing initial setup: Trying to find home server... Home Server = ServerA [ServerA] Directory Binding Error 1722: The RPC server is unavailable. This may limit some of the tests that can be performed. * Identified AD Forest. Done gathering initial info. Doing initial required tests Testing server: SiteA\ServerA Starting test: Connectivity [ServerA] DsBindWithSpnEx() failed with error 1722, The RPC server is unavailable.. Got error while checking LDAP and RPC connectivity. Please check your firewall settings. ......................... ServerA failed test Connectivity