Dan Herbert's

Due to an issue between Vista and Firefox, when doing development on localhost, Firefox has a serious issue with resolving DNS requests. This only happens on localhost, so this does not affect any development not being done on localhost.

The issue can only be described as “pages loading unbelievably slow” when localhost is being queried for resources under Vista.

Not to worry, however, there is a fix!

To fix this issue, you simply need to type ‘about:config’ into Firefox. You may get a cute disclaimer warning you to be careful. Promise you’ll be careful and then type the following into the filter:

network.dns.disableIPv6

Set this preference to ‘true’ by double-clicking it. Once this is set to true, your performance will instantly be dramatically increased.

I’m not sure if this is a problem on Vista or Firefox’s end, however Internet Explorer does not have this issue on Vista so my guess is Firefox is broken somehow…