Postfix sending to A not MX
Robert Heller
heller at deepsoft.com
Sun Feb 27 19:56:12 UTC 2022
At Sun, 27 Feb 2022 13:39:16 -0600 "Ubuntu user technical support,? not for general discussions" <ubuntu-users at lists.ubuntu.com> wrote:
>
> On 2/27/22 12:42 PM, Robert Heller wrote:
> > At Sun, 27 Feb 2022 08:33:15 -0800 "Ubuntu user technical support,? not for general discussions" <ubuntu-users at lists.ubuntu.com> wrote:
> >
> >>
>
> [snip]
>
>
> > It looks like you might not have a working DNS server.
> >
>
> I'm a little surprised that postfix uses DNS at all given the following
> line in the main.cf file:
>
> disable_dns_lookups = yes
>
> I don't run postfix, so maybe that setting does something other that the
> more obvious interpretation of its name.
>From postconf(5):
disable_dns_lookups (default: no)
Disable DNS lookups in the Postfix SMTP and LMTP clients. When
disabled, hosts are looked up with the getaddrinfo() system
library routine which normally also looks in /etc/hosts.
DNS lookups are enabled by default.
Postfix *does need* to do a DNS lookup to find MX records... If DNS lookups
are disabled, I suspect Postfix can't do that, which is probably the OP's
problem, if he in fact has that setting (and why would he have that setting
for a Postfix server sending mail directly out to the Internet). The only
reason to turn this setting on would be for an Intranet ([Office] LAN only)
mail server or one using a "smart host" (forwarding everthing to an uplink
relay).
I don't have that setting and am running with the default (no) on my mail
server (running Postfix).
>
>
>
> --
> Keith
>
--
Robert Heller -- Cell: 413-658-7953 GV: 978-633-5364
Deepwoods Software -- Custom Software Services
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