On Thu, May 04, 2017 at 05:18:55PM +0300, Marat Khalili wrote:
> > Postfix from me installs with IPv6 turned off. Complain with your
> > distributor if they change that.
>
> Indeed default inet_protocols value in my distribution is "all", both in
> configuration created by install script and when corresponding line is
> commented out. Do you mean, it is not supposed to be this way?
The compiled in default is "all", but the prototype "main.cf" file included
with Postfix sources has "ipv4".
$ postconf -d inet_protocols
inet_protocols = all
$ grep inet_protocols conf/main.cf
inet_protocols = ipv4
On Thu, May 04, 2017 at 05:17:01PM +0300, Marat Khalili wrote:
> > To disable outbound IPv6 in Postfix set "inet_protocols = ipv4". If you set
> > "inet_protocols" to some other value, then Postfix will do nexthop IPv6
> > lookups.
>
> What will happen in my current setup if AAAA response suddenly becomes
> non-empty? Will it fail to send the message?
Since IPv6 connections can't/won't complete, all messages will of
course be sent via IPv4. With the address family not enabled in the
kernel, IPv6 failure will be fast (likely the socket(PF_INET6, ...)
system call will fail) and the only effect is a bit more logging in
some cases and the time it takes to do the AAAA lookups.
--
Viktor.
