Although I do like Firefox and currently use it as my primary browser, I’m in the process of obtaining and compiling up the Kazehakase browser.

In the meantime, I’ve been getting annoyed with extremely slow browsing and an apparent keyboard delay on Firefox under Ubuntu 9.04. I don’t find the WordPress site the quickest, but a keyboard delay leading to missing characters when I’m typing makes it even more frustrating. Add in browsing at the speed of an arthritic sloth with terminal asthma and a limp, and I’ve succeeded in my quest of finding something new to shout at.

Anyway, after deciding that enough was decidedly enough, I searched for, and found, a reason for this problem. I’ll explain why this problem affected the keyboard in a moment, but the solution is as follows:

• Open Firefox and in the address bar type:

  about:config

• In the Filter bar, type:

  ipv6

• Double-click on network.dns.disableIPv6 to set the value to “true”
• Restart Firefox

Obviously I’m assuming that you’re operating in an IPv4 environment, like me. Disabling this setting rapidly speeded up my browsing and removed the keyboard delay. But why?

Well, the browsing bit is obvious. If Firefox is attempting to resolve my IPv4 DNS server over IPv6, then it simply can’t. This is adding in an overhead on the browse time. Disabling IPv6 resolution means that it always resolves using IPv4. So that’s one problem solved. The keyboard issue took a bit more thought before I realised what was happening.

Basically, it boils down to the same name resolution problem. When you search in Google, you get the handly little “suggestion” as you’re typing. Each time you type a letter, Firefox has to make another call to Google’s servers to adjust the suggestion. Therefore, we experience the “lag”. The same problem happens if you have inline spell-checking switched on, which is why WordPress and any other text form was slow.

Switching it off has made Firefox more usable again, and the only thing that causes keyboard delays now is my rather random typing style!

EDIT 30th October: Check out this post for how to disable IPv6 in Ubuntu completely – this makes other browsers such as Opera work quickly.