I've been having this problem for the past couple months: sometimes (particularly in the afternoon or evening when traffic is the greatest) my dedicated server goes unresponsive for about an hour or so--you can FTP into it (upload and download work fine), access the control panel, and ssh into it, but it refuses to serve up any webpages / files through the browser (no one can access my site). Meanwhile the CPU / RAM seems to be just sitting there being completely unused (CPU load is like 0.3 or less most of the time). This problem just starts by itself randomly and then goes away by itself somewhat randomly after a couple hours. Restarting the server has no effect on this. (And it's not an issue with my nameserver either--typing in my server's dedicated IP into the browser doesn't work either.) I'm puzzled.
I'd like someone to figure out what the problem is and fix it permanently. My server's running Fedora 6 / GoDaddy control panel if it helps. (My site's also a hentai (adult) site.) Thanks for looking and happy bidding!