how to set smtp-client -> submission_relay_host for IPv4 only?

[Aki Tuomi]

> On 16/10/2020 00:52 PGNet Dev <pgnet.dev at gmail.com> wrote:
> 
>  
> On 10/15/20 2:02 PM, jeremy ardley wrote:
> >> how/where do I configure (just) the dovecot smtp-client -> submission_relay_host to only connect IPv4?
> > 
> > It appears your host has A and AAAA records in your DNS. The clients will try IPV6 first if they see an AAAA record.
> > 
> > If you don't need IPV6 for your host remove the AAAA record. All connections will then only use IPV4.
> > 
> > If you need IPV6 for some other reason then create an alias DNS A record and point your clients to that instead
> 
> That's not the issue.
> 
> All my machines are dual stack.
> All my hosts' DNS records exist for both A & AAAA records.
> 
> Some services listen on only IPv4, some only on IPv6, some both.
> 
> For Dovecot _listeners_ it's trivial to set IPv4/6-only, or both, addresses.
> 
> It's also trivial to set OTHER clients, connecting TO Dovecot, to use IPv4-only.
> 
> I'm asking how/where to 'tell', via config, Dovecot's smtp-CLIENT, that's making to connection to the submission_relay_host, to use _only_ IPv4.

There is currently no (other) way to do this than using /etc/hosts or specifying IPv4 address for the relay host.

Aki