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

[Timo Sirainen]

On 3.5.2013, at 12.34, Jakob Hirsch <jh at plonk.de> wrote:

> 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

Software can also specify if they want that functionality or not. In Dovecot v1.0 [::] may have listened also on IPv4, but since v1.1 [::] has only listened on IPv6. So I guess the complaint wasn't really about Dovecot v2.x, but about v1.1+.

Hmm. So Debian stable is switching from Dovecot v1.0 -> v2.1? Maybe it would be worth mentioning this somewhere.