Just a short note with a problem we ran into this morning. Our XF setup was doing a lot of errors and duplicate posts. Pages loaded OK most of the time, but new threads and replies timed out. After trying everything (restart processes, taking caches off, etc.), I asked our ISP to look and he found that one of the DNS entries listed in resolv.conf was offline. Just posting this to add to the knowledge base since I didn't find a similar problem in a search here. "It was a DNS issues. One of the DNS servers listed in /etc/resolv.conf was offline, for some reason, this was slowing down your site."