On Fri, 27 Mar 2026 00:05:38 +1100 Viktor Dukhovni via Postfix-users <[email protected]> wrote:
> > since I have different set of options and restrictions for submission. > > You do that on ports 465 and 587 that allow outbound mail. > Port 25 is for *everyone* who can make the TCP connection. OK so this is where my confusion stems from. I just got confused by various online howtos that state "to disable MUA submission on port 25, set smtpd_sasl_auth_enable=no". My assumption was - MUA connects to port 25 and attempts to use SASL, but since smtpd_sasl_auth_enable=no the connection gets rejected because smtpd is not prepared to speak SASL. However this is not what happens and connection is permitted without SASL. So after digging around in my MUA settings: SMTP Auth: Enabled Auth method: Automatic it appears the above setting allows automatic downgrade to no SASL. If I change this to: Auth method: Plain then submitting mail to port 25 gives the expected error message: "authentication not enabled" I guess as far as Postfix is concerned, MUA is also an MTA, and any MUA can send mail on port 25 without SASL if it chooses so. _______________________________________________ Postfix-users mailing list -- [email protected] To unsubscribe send an email to [email protected]
