User-agent: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.5) Gecko/20031013 Thunderbird/0.3
If an application can use both IPv4 and IPv6, and IPv6 PDP contexts are
available, it is preferable to try IPv6 communication first.
i don't like this 'try ipv6' paradigm. either ipv6 is there and is
working without i need to try it, or it is not there and is not working.
how many times do i have to try it before i will think it stinks and
will stop trying and simply disable it and stick to ipv4?