Postfix + Ubuntu: SASL LOGIN authentication failed: authentication failure

On Ubuntu 18.04 server, I use Webmin and Virtualmin to manage the server and the virtual host.

Looking at the file: /var/log/mail.log

I have this:

Sep 5 12:11:50 ns3147326 postfix/smtpd[17356]: warning: unknown[92.118.38.51]: SASL LOGIN authentication failed: authentication failure Sep 5 12:11:50 ns3147326 postfix/smtpd[17356]: disconnect from unknown[92.118.38.51] ehlo=1 auth=0/1 rset=1 quit=1 commands=3/4 

Giving this command service saslauthd status and I obtain:

● saslauthd.service - LSB: saslauthd startup script Loaded: loaded (/etc/init.d/saslauthd; generated) Active: active (running) since Thu 2019-09-05 12:15:18 CEST; 31min ago Docs: man:systemd-sysv-generator(8) Process: 21744 ExecStop=/etc/init.d/saslauthd stop (code=exited, status=0/SUCCESS) Process: 21762 ExecStart=/etc/init.d/saslauthd start (code=exited, status=0/SUCCESS) Tasks: 10 (limit: 4915) CGroup: / ├─19961 /usr/sbin/saslauthd -a pam -c -m /var/run/saslauthd -n 5 ├─19962 /usr/sbin/saslauthd -a pam -c -m /var/run/saslauthd -n 5 ├─19963 /usr/sbin/saslauthd -a pam -c -m /var/run/saslauthd -n 5 ├─19964 /usr/sbin/saslauthd -a pam -c -m /var/run/saslauthd -n 5 ├─19965 /usr/sbin/saslauthd -a pam -c -m /var/run/saslauthd -n 5 ├─21783 /usr/sbin/saslauthd -a pam -c -m /var/spool/postfix/var/run/saslauthd -r -n 5 ├─21784 /usr/sbin/saslauthd -a pam -c -m /var/spool/postfix/var/run/saslauthd -r -n 5 ├─21785 /usr/sbin/saslauthd -a pam -c -m /var/spool/postfix/var/run/saslauthd -r -n 5 ├─21786 /usr/sbin/saslauthd -a pam -c -m /var/spool/postfix/var/run/saslauthd -r -n 5 └─21787 /usr/sbin/saslauthd -a pam -c -m /var/spool/postfix/var/run/saslauthd -r -n 5 set 05 12:46:56 ns3147326 saslauthd[21784]: pam_unix(smtp:auth): check pass; user unknown set 05 12:46:56 ns3147326 saslauthd[21784]: pam_unix(smtp:auth): authentication failure; logname= uid=0 euid=0 tty= ruser= rhost= set 05 12:46:57 ns3147326 saslauthd[21784]: DEBUG: auth_pam: pam_authenticate failed: Authentication failure set 05 12:46:57 ns3147326 saslauthd[21784]: : auth failure: [user=] [service=smtp] [realm=ip-51-75-135.eu] [mech=pam] [reason=PAM auth error] 

I googled the problem but I can't find the solution.

This is my /etc/postfix/main.cf:

# See /usr/share/postfix/main.cf.dist for a commented, more complete version # Debian specific: Specifying a file name will cause the first # line of that file to be used as the name. The Debian default # is /etc/mailname. #myorigin = /etc/mailname smtpd_banner = $myhostname ESMTP $mail_name (Ubuntu) biff = no # appending .domain is the MUA's job. append_dot_mydomain = no # Uncomment the next line to generate "delayed mail" warnings #delay_warning_time = 4h readme_directory = no # See -- default to 2 on # fresh installs. compatibility_level = 2 # TLS parameters smtpd_tls_cert_file = /etc/ssl/certs/ssl-cert-snakeoil.pem smtpd_tls_key_file = /etc/ssl/private/ssl-cert-snakeoil.key smtpd_use_tls=yes smtpd_tls_session_cache_database = btree:${data_directory}/smtpd_scache smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache # See /usr/share/doc/postfix/TLS_README.gz in the postfix-doc package for # information on enabling SSL in the smtp client. smtpd_relay_restrictions = permit_mynetworks permit_sasl_authenticated defer_unauth_destination myhostname = ns3147326.ip-51-75-135.eu alias_maps = hash:/etc/aliases alias_database = hash:/etc/aliases myorigin = $mydomain mydestination = $myhostname, localhost.$mydomain, $mydomain, localhost, localhost.localdomain mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128 mailbox_size_limit = 0 recipient_delimiter = + inet_protocols = all virtual_alias_maps = hash:/etc/postfix/virtual sender_bcc_maps = hash:/etc/postfix/bcc mailbox_command = /usr/bin/procmail-wrapper -o -a $DOMAIN -d $LOGNAME home_mailbox = Maildir/ smtpd_sasl_auth_enable = yes broken_sasl_auth_clients = yes smtpd_recipient_restrictions = permit_mynetworks permit_sasl_authenticated reject_unauth_destination smtp_tls_security_level = may allow_percent_hack = no milter_default_action = accept milter_protocol = 2 smtpd_milters = inet:localhost:8891 non_smtpd_milters = inet:localhost:8891 mynetworks_style = subnet 

This is my /etc/default/saslauthd:

# # Settings for saslauthd daemon # Please read /usr/share/doc/sasl2-bin/README.Debian for details. # # Should saslauthd run automatically on startup? (default: no) START=yes # Description of this saslauthd instance. Recommended. # (suggestion: SASL Authentication Daemon) DESC="SASL Authentication Daemon" # Short name of this saslauthd instance. Strongly recommended. # (suggestion: saslauthd) NAME="saslauthd" # Which authentication mechanisms should saslauthd use? (default: pam) # # Available options in this Debian package: # getpwent -- use the getpwent() library function # kerberos5 -- use Kerberos 5 # pam -- use PAM # rimap -- use a remote IMAP server # shadow -- use the local shadow password file # sasldb -- use the local sasldb database file # ldap -- use LDAP (configuration is in /etc/saslauthd.conf) # # Only one option may be used at a time. See the saslauthd man page # for more information. # # Example: MECHANISMS="pam" MECHANISMS="pam" # Additional options for this mechanism. (default: none) # See the saslauthd man page for information about mech-specific options. #OPTIONS="-c -m /var/spool/postfix/var/run/saslauthd -r" # How many saslauthd processes should we run? (default: 5) # A value of 0 will fork a new process for each connection. THREADS=5 # Other options (default: -c -m /var/run/saslauthd) # Note: You MUST specify the -m option or saslauthd won't run! # # WARNING: DO NOT SPECIFY THE -d OPTION. # The -d option will cause saslauthd to run in the foreground instead of as # a daemon. This will PREVENT YOUR SYSTEM FROM BOOTING PROPERLY. If you wish # to run saslauthd in debug mode, please run it by hand to be safe. # # See /usr/share/doc/sasl2-bin/README.Debian for Debian-specific information. # See the saslauthd man page and the output of 'saslauthd -h' for general # information about these options. # # Example for chroot Postfix users: "-c -m /var/spool/postfix/var/run/saslauthd" # Example for non-chroot Postfix users: "-c -m /var/run/saslauthd" # # To know if your Postfix is running chroot, check /etc/postfix/master.cf. # If it has the line "smtp inet n - y - - smtpd" or "smtp inet n - - - - smtpd" # then your Postfix is running in a chroot. # If it has the line "smtp inet n - n - - smtpd" then your Postfix is NOT # running in a chroot. #OPTIONS="-c -m /var/spool/postfix/var/run/saslauthd -r" #PARAMS="-m /var/spool/postfix/var/run/saslauthd -r" #OPTIONS="-c -m /var/spool/postfix/var/run/saslauthd" OPTIONS="-c -m /var/spool/postfix/var/run/saslauthd -r" PARAMS="-m /var/spool/postfix/var/run/saslauthd -r" 

How can I solve?

1 Answer

Apply netplan with it's default .yaml file(from the FRESH install of 18.04)

Then configure networking thru Webmin. It will create the readable netplan .yaml file it needs.