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.
