Fun with Microsoft DNS

So being a true geek, one of our technicians decided to pick a geeky name for his new Windows XP system. Since he already had a linux system named 'null', he decided to call his new XP box 'localhost'. Little did he know...

For the better part of two weeks now we've been troubleshooting weird and unexplained network issues. For one, the new XP box was slower than ketchup from a Heinz bottle. Ironically, an identically configured XP box worked just fine. This led to all sorts of RAM, CPU, I/O, and IRQ troubleshooting that got us no where. Most strangely, many of our apps that used to work just fine were now timing out or hanging indefinitely. We replaced and bypassed switches and hubs, network cabling. You name it, we did it. And after two weeks of frustration, the whole company was involved.

It wasn't until someone stumbled across the Microsoft DNS server that we discovered our problem. We have a Windows 2000 domain with ADS, which means DDNS (Dynamic DNS). All host names are automatically pushed into DNS for us. And, for some historical reason that no one here could explain, all our Linux servers (+20) had their nsswitch.conf file set to read DNS *before* the local hosts file. So every request that one of our Linux machines made that was supposed to go the localhost IP address (127.0.0.1) was instead going to the new Windows XP system. This explained the weird timeouts and the slowness of the XP system. Once we changed the name, flushed DNS cache, and restarted DNS services, all worked perfectly fine.

So why have we added this little story to our website? Because it goes to show that there's a line at how *geeky* one should be. :)