Probably
That's what I get for not noticing this post right away: My recollection is that the server's DNS system was down for several hours in the morning, either Saturday or Friday. Needed a reboot, then everything was back to normal.
I'm starting to think that Linux's reputation for superior reliability is bogus. I never had to reboot my old Windows 2000 server this often, nor did I feel like I had to constantly scurry around fixing all the little things that seem to constantly break on a Linux system.