Check IPv6 enabled tracker in torrent

Here's an ugly oneliner to see if a torrent has IPv6 enabled trackers in it:

$ strings ubuntu-14.04.2-desktop-amd64.iso.torrent | head -1 | tr '/' '\n' | awk -F: ' $1 ~ /\./ { print "host -t aaaa "  $1 }' | /bin/sh | grep -vi "has no AAAA"

ipv6.torrent.ubuntu.com is an alias for ubuntuv6tracker.bit.nl.
ubuntuv6tracker.bit.nl has IPv6 address 2001:7b8:3:37::21:3

So, yes, this torrent has an IPv6 enabled tracker.

I got this torrent from http://ipv6.torrent.ubuntu.com/, which only works via IPv6.