Archive for the 'Firefox' Category

Speed up Firefox on Linux - Disable IPv6 Lookups

July 27th, 2007 Comments(0)

Was playing around with PCLinuxOS (I like to try several flavors of Linux) and found Firefox taking forever to resolve host names to IP addresses. Status bar would be stuck on “Looking up www.whoever.com.”

Now being the tech person I am, I prefer to run my own DNS server — especially since my ISP’s DNS servers are always slow. I know I had it set up right and direct DNS queries from the command line came back almost instantly. So why was Firefox taking forever finding IP addresses for the sites I was trying to connect with?

Digging through Firefox’s config, I came across the network.dns.disableIPv6 setting. Then I remembered! IPv6 is usually enabled in Linux by default. Firefox, and just about everything else on Linux, will try to establish an IPv6 connection first if it can. If it can’t, say no IPv6 address exist for the host you’re trying to connect with, then it falls back on IPv4. But even worse, if an IPv6 address does exist for the host your connecting to but your ISP doesn’t support IPv6, Firefox will try to connect anyway until it gets a ‘destination not available’ before falling back to IPv4.

So the simple solution is to tell Firefox not to use IPv6. To do this:

  1. Type “about:config” for the URL in Firefox and hit enter (without the quotes, of course).
  2. In the filter field, type “DNS” and hit enter.
  3. Double-click on “network.dns.disableIPv6″, changing its value from False to True.

That’s it. You should notice a considerable improvement in Firefox’s speed.