OS X Server 10.6 and Fully Qualified Domain Names From the Advanced Server Admin for OS X Server v.10.6:


  You must have a fully qualified domain
  name for each server’s IP addess in
  the DNS system. The DNS zone must have
  the reverse-lookup record for the name
  and address pair. Not having a stable,
  functioning DNS system with reverse
  lookup leads to service failures and
  unexpected behaviors.


I was recently bit by this requirement as my internal network doesn't have an internal DNS server. As a result, various applications and services (User Management in particular),  hosted on my XServe have experienced degraded performance. My question is, besides deploying my own DNS server (dnsmasq or bind9) is there any other way to provide a FQDN (Fully Qualified Domain Name) for my X Serve? 

UPDATE

Used the X Serve as its own DNS host, worked like a charm with very little configuration.
No, the only way to get a FQDN is by using a DNS server, either external to your Xserve or run on the Xserve itself. It's recommended with setting up Mac OS X to set up DNS first before anything else.