Here on Vultr, we have the option to enable IPv6 on all deployable VPSes. But with this, some programs and commands may prefer one or the other with unpredictable results.
In this guide, we will configure
apt-get to use only IPv4 or IPv6. This guide targets Ubuntu 14.04 and Debian Jessie, but may work for newer versions as well.
If you want to force the apt-get to use IPv4 or IPv6 only one time, follow these steps. This feature is available after the
0.9.7.9~exp1 version of
apt-get. First, make sure your version of
apt-get is newer than
0.9.7.9~exp1 by running the following command:
The result will be something like this:
apt 1.0.1ubuntu2 for amd64 compiled on Oct 28 2014 20:55:14
If the version checks out, then you can force IPv4 with:
apt-get -o Acquire::ForceIPv4=true update
apt-get -o Acquire::ForceIPv6=true update
This will update the repositories resolving the URLs in sources.list to IPv4 only.
To make the setting persistent, create the file
Put the following contents in it:
Save the file, and you're good to go. If you want to force IPv6 instead, change the 4 to 6 in the file name and settings. To choose between one of them, test with the fast method and see which works better.