YSlow show Localhost DNS too slow to response

YSlow show loading javascript from localhost is very slow and DNS response take the most time.

This is really irritating for me as I am always working with Firefox and Fire bug to debug my website development.

I googled and found the solution in this website.

The solution is simple change the firefox config:

1. type about:config in address bar
2. click I'll be careful, I promise!
3. Type network.dns.disableIPv6 in filter
4. Double click on network.dns.disableIPv6

Value will turn to true and you are done. Refresh your localhost website.