No.
You're only trying to send mail. Your ISP is only trying to stop you from
sending mail.
Mail delivery is meant to be very well defined and easy to identify. If your
ISP is blocking connections to port 25 then they are blocking all mail, spam
and otherwise. The solution is to set up a mail server on a network that
allows mail. This can be a $5/mo cloud server. You can then 'submit' mail to
your mail server using other ports, but the mail server will talk to other mail
servers on standard ports, primarily port 25.
ED.
> On 2021, Apr 22, at 3:18 PM, [email protected] wrote:
>
> Hi. Is it possible to configure smtpd to relay via a port other than port 25?
> Since my ISP is blocking port 25, it seems smtpd is failing to perform MX
> lookups (or some other step?) when I try to send mail, as seen via "tail -f
> /var/log/maillog". At least, the only solution I've succeeded with so far is
> to use an external SMTP service (whereby a different port can be set), which
> I'm trying to avoid if possible. I'm only trying to send mail, nothing else.
>
> Sample maillog output:
>
> Apr 22 21:02:12 openbsd smtpd[85598]: smtp-out: Enabling route [] <-> x.x.x.x
> Apr 22 21:02:12 openbsd smtpd[85598]: smtp-out: x mta connecting
> address=smtp://x.x.x.x:25 host=x
> Apr 22 21:02:12 openbsd smtpd[85598]: smtp-out: x mta error reason=Connection
> timeout
> Apr 22 21:02:12 openbsd smtpd[85598]: smtp-out: Disabling route [] <-> x.x.x.x
> Apr 22 21:02:27 openbsd smtpd[85598]: smtp-out: Enabling route [] <-> x.x.x.x
> Apr 22 21:02:27 openbsd smtpd[85598]: smtp-out: x mta error reason=IO Error:
> No route to host
> Apr 22 21:02:27 openbsd smtpd[85598]: smtp-out: Disabling route [] <-> x.x.x.x
> Apr 22 21:02:27 openbsd smtpd[85598]: smtp-out: x mta connecting
> address=smtp://x.x.x.x:25 host=x
