Autenticazione con Postfix non funziona

daniele · Post by **daniele** » 12 May 2025, 16:28

SCENARIO: un mailserver invia email in uscita tramite uno smarthost mailrelay Postfix e nella coda del mailserver i messaggi non escono e c'è errore di autenticazione con il mailrelay

1) Controllare il log di Postfix; se vedete messaggi tipo questi, dove trovare l'IP e il nome del mailsterver e il nome dello user di autenticazione, allora il servizio saslauthd ha problemi

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2025-05-12T16:08:58.341423+02:00 smtp postfix/smtpd[2765]: warning: SASL authentication failure: cannot connect to saslauthd server: No such file or directory
2025-05-12T16:08:58.341675+02:00 smtp postfix/smtpd[2765]: warning: mdaemon[192.168.1.1]: SASL LOGIN authentication failed: generic failure, sasl_username=<auth_user>
2025-05-12T16:08:58.341868+02:00 smtp postfix/smtpd[2765]: lost connection after AUTH from mdaemon[192.168.1.1]
2025-05-12T16:08:58.341972+02:00 smtp postfix/smtpd[2765]: disconnect from mdaemon[192.168.1.1] ehlo=2 starttls=1 auth=0/1 commands=3/4
2025-05-12T16:08:58.345223+02:00 smtp postfix/smtpd[2760]: connect from mdaemon[192.168.1.1]
2025-05-12T16:08:58.366166+02:00 smtp postfix/smtpd[2760]: Anonymous TLS connection established from mdaemon[192.168.1.1]: TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256
2025-05-12T16:08:58.371116+02:00 smtp postfix/smtpd[2760]: warning: SASL authentication failure: cannot connect to saslauthd server: No such file or directory
2025-05-12T16:08:58.371292+02:00 smtp postfix/smtpd[2760]: warning: mdaemon[192.168.1.1]: SASL LOGIN authentication failed: generic failure, sasl_username=<auth_user>

2) Controllare che saslauthd sia in esecuzione

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sudo systemctl status saslauthd

Se il servizio è avviato vedrete una schermata simile a questa:

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? saslauthd.service - SASL Authentication Daemon
     Loaded: loaded (/usr/lib/systemd/system/saslauthd.service; [b]enabled[/b]; preset: [b]enabled[/b])
     Active: [b]active (running)[/b] since Mon 2025-05-12 16:12:38 CEST; 2min 35s ago
       Docs: man:saslauthd(8)
    Process: 803 ExecStart=/usr/sbin/saslauthd -a $MECHANISMS $MECH_OPTIONS $OPTIONS -n $THREADS (code=exited, status=0/SUCCESS)
   Main PID: 822 (saslauthd)
      Tasks: 5 (limit: 3950)
     Memory: 8.3M (peak: 8.8M)
        CPU: 57ms
     CGroup: /system.slice/saslauthd.service
             +-822 /usr/sbin/saslauthd -a pam -c -m /var/spool/postfix/var/run/saslauthd -n 5
             +-823 /usr/sbin/saslauthd -a pam -c -m /var/spool/postfix/var/run/saslauthd -n 5
             +-824 /usr/sbin/saslauthd -a pam -c -m /var/spool/postfix/var/run/saslauthd -n 5
             +-825 /usr/sbin/saslauthd -a pam -c -m /var/spool/postfix/var/run/saslauthd -n 5
             +-826 /usr/sbin/saslauthd -a pam -c -m /var/spool/postfix/var/run/saslauthd -n 5

May 12 16:12:38 mail2 systemd[1]: Starting saslauthd.service - SASL Authentication Daemon...
May 12 16:12:38 mail2 saslauthd[822]:                 : master pid is: 822
May 12 16:12:38 mail2 saslauthd[822]:                 : listening on socket: /var/spool/postfix/var/run/saslauthd/mux
May 12 16:12:38 mail2 systemd[1]: Started saslauthd.service - SASL Authentication Daemon.

3) Abilitare di default l'avvio di saslauthd

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sudo systemctl enable saslauthd

Questo dovrebbe anche avviare il servizio, comunque consiglio di controllare dando nuovamente

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sudo systemctl status saslauthd