You are hosting your own DNS on Windows Server 2003 or likewise. Occasionally (especially after rebooting the DNS server), hostmame lookup does not occur, for example, ping or http request to your local host(s) from a web browser.
I do not know why or what is happening with this and I don't have time to figure out really what's gogin on but what helps are two things,
From a command line, try typing in "ipconfig /flushdns"
If that does not work you can try the following;
- Allow Dynamic updates on your Primary DNS nodes from the DNS configuration applet.
- Create reverse lookup zones.