sendmail vs ipv6 broken after upgrade to 9.1

[Ulrich Spörlein]

On Tue, 2013-01-08 at 18:36:34 +0100, Michiel Boland wrote:
> On 01/08/2013 16:18, Ulrich Spörlein wrote:
> > Hey,
> >
> > I upgraded a server running 8.x to 9.1 over the weekend and sendmail no
> > longer wants to bind the AF_INET6 sockets.
> >
> > So while this still works:
> >
> > DAEMON_OPTIONS(`Port=smtp, Addr=127.0.0.1, Name=MSA, M=Eu, InputMailFilters=dkim')
> > DAEMON_OPTIONS(`Port=smtp, Addr=::1, Name=MSA, Family=inet6, M=Eu, InputMailFilters=dkim')
> >
> > this is broken:
> >
> > DAEMON_OPTIONS(`Port=submission, Addr=acme.spoerlein.net, Name=MSA, M=E, InputMailFilters=dkim')
> > DAEMON_OPTIONS(`Port=submission, Addr=acme.spoerlein.net, Name=MSA, Family=inet6, M=E, InputMailFilters=dkim')
> >
> > which makes me believe this has to do with name resolution...
> >
> > The actual reported errors are:
> >
> > Jan  8 16:05:03 acme sm-msp-queue[98057]: starting daemon (8.14.6): queueing at 00:30:00
> > Jan  8 16:05:03 acme sm-mta[98054]: NOQUEUE: SYSERR(root): opendaemonsocket: daemon MSA: cannot bind: Can't assign requested address
> 
> What's the output of the 'ip6addrctl' command on your machine?
> 
> Cheers
> Michiel

root at acme: ~# ip6addrctl
Prefix                          Prec Label      Use
::ffff:0.0.0.0/96                 50     0        0
::1/128                           40     1        0
::/0                              30     2    72866
2002::/16                         20     3        4
::/96                             10     4        0

Gah! I remember having to set ip6addrctl_policy="ipv6_prefer" on another
system that I upgraded to 9.x a long time ago.

After setting this, it now looks like this:
root at acme: ~# ip6addrctl
Prefix                          Prec Label      Use
::1/128                           50     0        0
::/0                              40     1        0
2002::/16                         30     2        0
::/96                             20     3        0
::ffff:0.0.0.0/96                 10     4        0

And even sendmail is happily finding the sockets to bind to. Thanks for the hint!

The bigger question now is, why don't we want to have a working IPv6 out of the
box?

Regards,
Uli