While upgrading a vCenter Server 5.0 to 5.0U1 I received a message that my FQDN had an issue:
However, a ping showed me that the FQDN resolved just fine. A little digging turned up an issue I was not aware of – the install routing will try both a name resolution and an IP lookup – returning “The Fully Qualified Domain Name cannot be resolved.” if either search fails. I have not specifically had a problem , but I’ll go make the PTR entry just to be sure.