Slow updating of composer dependencies, despite --prefer-dist flag

Question

Why does it take up to two minutes for my composer dependencies to update, even when there have been no changes?

A popular suggestion is to append the --prefer-

Answer 1

I had a problem due to having IPv6 enabled. Running the following fixed this problem:

sudo sh -c "echo 'precedence ::ffff:0:0/96 100' >> /etc/gai.conf"

You can find more information here: https://getcomposer.org/doc/articles/troubleshooting.md#operation-timed-out-ipv6-issues-