Do you know what IPv6 is? If you don't then it's unlikely you need it, even though it's activated by default under Ubuntu. IPv6 is the new network addressing scheme that's designed to replace IPv4, which is used across the Internet right now. One day we'll probably all use it but at the moment you'll struggle to find it used outside of academic institutions and some corporate environments. The trouble is that having IPv6 enabled can cause program incompatibilities and even network slowdowns, especially with certain types of router and/or ISPs. To disable it, follow these steps:
1. Open a terminal window and type gksu gedit /etc/modprobe.d/aliases. In the Gedit window, look for the line that reads alias net-pf-10 ipv6 and change ipv6 to off, so it reads alias net-pf-10 off. Then save the file.
2. Open the /etc/hosts file in Gedit (gksu gedit /etc/hosts) and, after the line that reads # The following lines are desirable for IPv6 capable hosts, put a hash at the beginning of each line following that contains ip6 within it (so the first line will read #::1 ip6-localhost ip6-loopback; the second #fe00::0 ip6-localnet, and so on). See Figure 3.18 for how the file looked after editing on my test PC. Once done, save the file and quit Gedit.
3. Start Firefox and, in the address bar, type about:config. You can ignore the warning that appears about changing settings. In the Filter text field, type ipv6. Then double-click network.dns.disableIPv6 so that it now appears in bold (and you might notice that, at the end of the line, false changes to true). Then close Firefox and reboot your computer.
Was this article helpful?