Recently my ISP migrated (and upgraded?) all their servers to a new physical location. I noticed my WAN side IP address has since changed and my DNS servers' IPs are also new. Since then, I've been getting frequent "Connection Timed Out" results from HTTP requests in Firefox. Pressing Retry typically works but it was the delay in page loading was becoming quite annoying.
I found a tweak that seems to have fixed my problem.
Originally Posted by Mozilla
One particular bug that has appeared exists not in Mozilla, but in IPv6-capable DNS servers: an IPv4 address may be returned when an IPv6 address is requested. It is possible for Mozilla to recover from this misinformation, but a significant delay is introduced.
By going into about
:config and setting network.dns.disableIPv6 to TRUE, I have resolved my problem.
I no longer have to wait 10 seconds for the Timeout page to show up so I can press the Retry button.
Just thought I'd pass this on since it's likely that other people's ISPs will be upgrading their DNS servers to be IPv6-capable in the near future as well.