Dovecot SMTPD Sasl auth error: fatal: no SASL authentication mechanisms

Question

I've googled this error and nothing I've read/tried works - anyone know what it is

Error log:

Feb 23 22:35:36 localhost postfix/smtpd[5278]: connect from localhost.localdomain[127.0.0.1]
Feb 23 22:35:36 localhost postfix/smtpd[5278]: warning: SASL: Connect to smtpd failed: No such file or directory
Feb 23 22:35:36 localhost postfix/smtpd[5278]: fatal: no SASL authentication mechanisms
Feb 23 22:35:37 localhost postfix/master[5214]: warning: process /usr/libexec/postfix/smtpd pid 5278 exit status 1
Feb 23 22:35:37 localhost postfix/master[5214]: warning: /usr/libexec/postfix/smtpd: bad command startup -- throttling

postfix/main.cf:

queue_directory = /var/spool/postfix
smtpd_sasl_type = dovecot
smptd_sasl_path = private/auth
broken_sasl_auth_clients = yes
smtpd_sasl_auth_enable = yes
smtpd_sasl_authenticated_header = yes

dovecot/conf.d/10-master.conf:

  # Postfix smtp-auth
  unix_listener /var/spool/postfix/private/auth {
    mode = 0666
    user = postfix
    group = postfix
  }

Dovecot is available in postfix:

[root@localhost ~]# postconf -a
cyrus
dovecot

Socket:

[root@localhost conf.d]# ls -l /var/spool/postfix/private/auth
srw-rw-rw-. 1 postfix postfix 0 Feb 23 22:46 /var/spool/postfix/private/auth

Telnet time out straight away:

[root@localhost ~]# telnet localhost 25
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
Connection closed by foreign host.

Auth works:

[root@localhost ~]# doveadm auth adrian
Password:
passdb: adrian auth succeeded
extra fields:
  user=adrian

OS: Centos 6.4 Dovecot: 2.1.17 Postfix: 2.6.6

Edit result of postconf -n:

[root@localhost ~]# postconf -n
alias_database = hash:/etc/aliases
alias_maps = hash:/etc/aliases
broken_sasl_auth_clients = yes
command_directory = /usr/sbin
config_directory = /etc/postfix
daemon_directory = /usr/libexec/postfix
data_directory = /var/lib/postfix
debug_peer_level = 2
html_directory = no
inet_interfaces = localhost
inet_protocols = all
mail_owner = postfix
mailq_path = /usr/bin/mailq.postfix
manpage_directory = /usr/share/man
mydestination = $myhostname, localhost.$mydomain, localhost
mynetworks = 192.168.124.0/24 168.100.189.0/28, 127.0.0.0/8
newaliases_path = /usr/bin/newaliases.postfix
queue_directory = /var/spool/postfix
readme_directory = /usr/share/doc/postfix-2.6.6/README_FILES
relay_domains = hash:/etc/postfix/relay_domains
sample_directory = /usr/share/doc/postfix-2.6.6/samples
sendmail_path = /usr/sbin/sendmail.postfix
setgid_group = postdrop
smtpd_recipient_restrictions = permit_mynetworks        permit_sasl_authenticated        reject_unauth_destination
smtpd_sasl_auth_enable = yes
smtpd_sasl_authenticated_header = yes
smtpd_sasl_type = dovecot
transport_maps = hash:/etc/postfix/transport
unknown_local_recipient_reject_code = 550

Answer 1

As you can see, there's no smtpd_sasl_path in our output of postconf -n

Why? The answer is easy. Because there's no smtpd_sasl_path set. Have a look at your first snippet: There's a typo in it. You wrote smptd_sasl_path = private/auth -- but there's a difference between smtpd and smptd.

Because Postfix doesn't have informations where to find the socket, Postfix is claiming the "failing connect".

Fix it and it'll work. :-)

And, at the end: Remember for the next time: Reading postconf -n carefully and make sure, that Postfix has the same information as you believe Postfix should have, is always an important step to find the failure.

Answer 2

Had the same error, different issue.

Had to edit /etc/dovecot/conf.d/10-master.conf and uncomment unix_listener and add the user and group lines.

service auth {
   unix_listener /var/spool/postfix/private/auth {
      mode = 0660
      user = postfix
      group = postfix
   }