Postfix smtpd_sasl_auth_enable = yes no working

Helo! If I postfix smtpd_sasl_auth_enable = yes in main.cf
telnet 127.0.0.1 25 no answer and 25 port local not work or telnet 192.168.xx.xx in local network 25 port no answer.
Escape character is ‘^]’.
Connection closed by foreign host.

Firewal and selinux is off
Why not working smtpd_sasl_auth_enable ?
posfix ver 2:3.5.9-24.el9 rocky linux 9.4

If not enabled smtpd_sasl_auth_enable = yes ( #smtpd_sasl_auth_enable = no )
Trying 127.0.0.1…
Connected to 127.0.0.1.
Escape character is ‘^]’.
220 mail.xx.xx ESMTP
But there is no authorization
everything works
Please help! I don’t understand something

In another distrib for exaple Rocky 8.10 (postfix 2:3.5.8-7.el8 ), Debian12 everything works

Hi, @au7

First, check the Postfix logs for any specific SASL or authentication errors. The logs are usually located in /var/log/maillog or /var/log/mail.log.

sudo tail -f /var/log/maillog

Next Make sure your SASL configuration is correct. In particular, check the following:

  • smtpd_sasl_path: Make sure it points to the correct SASL directory:
smtpd_sasl_path = smtpd
  • smtpd_sasl_type: Specify the type of SASL used. For example:
smtpd_sasl_type = cyrus

or

smtpd_sasl_type = dovecot

3. Check SASL installation

Verify that the necessary SASL packages are installed. For example, for Cyrus SASL, you should have packages like cyrus-sasl, cyrus-sasl-lib and cyrus-sasl-plain installed.

sudo dnf install cyrus-sasl cyrus-sasl-plain cyrus-sasl-lib

4. Check SELinux configuration

Even if SELinux is disabled, previous configurations may still cause problems. Make sure SELinux is completely disabled and check that no residual rules are interfering.

sudo sestatus

If you still have problems post your log error here :wink:

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I found a solution
1 dnf install cyrus-sasl-plain !!!

Thaks! Topic may closed

1 Like

Let me add an interesting fact about postfix: it’s configuration directives often differ by a single “d” letter, for example there are both smtpd_sasl_auth_enable and smtp_sasl_auth_enable parameters.
The quick and dirty way to understand the difference between those is that

  • smtp daemon (== persistent process) handles email transfer between servers, while
  • smtpd daemon is what you utilize (along with IMAP or POP3) on your email client to fetch emails from the server.

I once modified an image I googled (to explain ports used by email servers, on another forum) - but let me also leave it here, to illustrate what I have in mind:

mta_flow - modified PL

In the image (and in real life ;]) Postfix acts as both MDA and MTA-relay.