[Dovecot] dual stack issue (was: Dovecot has no understandable configuration any more)

[Jakob Hirsch]

forum, 30.04.2013 16:55:

> Now i have found the solution.
> It seems to help to ask you. ;)
> 
> The solution was to change from
> listen = [::]
> to
> listen = *, [::]
> 
> There is no explanation for it - just try and error ...

This is not dovecot's fault. See here: http://serverfault.com/a/39561

In short: In Linux, binding to :: means "bind to both ipv6 and ipv4".
Setting /proc/sys/net/ipv6/bindv6only to 1 changes this behaviour, and
Debian had this by default in some testing versions of squeeze, as was
recently discussed on the asterisk-users list:
http://lists.digium.com/pipermail/asterisk-users/2013-March/278296.html