If you have a dns server it should be considered hosting a domain so even in
a work group setting you need to be hosting a domain name. I'm guessing you
aren't doing this.
Follow below, it doesn't matter that you are a work group.
From KB 259302
414 (Warning) DNS_EVENT_SINGLE_LABEL_HOSTNAME
The DNS server computer currently has no DNS domain name. Its DNS name is a
single label hostname with no domain (example: "host" rather than
"host.microsoft.com").
You might have forgotten to configure a primary DNS domain for the server
computer. For more information, see either "DNS server log reference" or "To
configure the primary DNS suffix for a client computer" in the online Help.
While the DNS server has only a single label name, all zones created will
have default records (SOA and NS) created using only this single label name
for the server's hostname. This can lead to incorrect and failed referrals
when clients and other DNS servers use these records to locate this server
by name.
To correct this problem: 1. Open Control Panel.
2. Start the System tool.
3. Click the Network Identification tab.
4. Click Properties.
5. Type a domain name or work group name. This is used as your DNS
domain name.
6. Reboot the computer to initialize with new domain name.
After the reboot, the DNS server will attempt to fix up default records,
substituting new DNS name of this server, for old single label name.
However, you should review to make sure zone's SOA and NS records now
properly use correct domain name of this server.
--
Paul Bergson MCT, MCSE, MCSA, Security+, CNE, CNA, CCA
http://www.pbbergs.com
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