solved common erros 100

missing 587

SSL_accept error from: lost connection
Sep 30 22:10:01 postfix/smtps/smtpd[53161]: lost connection after CONNECT from unknown[192.168.0.1]
Sep 30 22:10:01 postfix/smtps/smtpd[53161]: disconnect from unknown[192.168.0.1] commands=0/0
Sep 30 22:10:01  postfix/smtps/smtpd[53311]: connect from unknown[192.168.0.1]
Sep 30 22:10:31 postfix/smtps/smtpd[53311]: SSL_accept error from unknown[192.168.0.1]: lost connection

6
nano /etc/postfix/master.cf and delete #:

    vi /etc/postfix/master.cf

submission inet n       –       –       –       –       smtpd

 

after that safe and restar tpostfix:

    /etc/init.d/postfix restart

POSTFIX fatal: no SASL authentication mechanisms

32

You can have saslauthd installed but not have any mechanisms installed. It's quite frustrating and poor error-proofing, IMO.

"no applicable SASL mechanisms" literally means it can't find any of its mechanisms. On a Fedora-based system you'd need to install the cyrus-sasl-plain package if you want to use the 'PLAIN' auth mechanisms (i.e. SMTP/STARTTLS).

yum install cyrus-sasl-plain

or

apt-get install libsasl2-modules



Many thanks! It's really hard to find the cause of such issues and the messages in the logs don't help - only as keywords in search to find such awesome answers. You saved my day. – hgoebl Apr 15 '19 at 10:35
After apt install libsasl2-dev it worked on my machine. 


6

the solution was very simple, the SASL daemon was down. /etc/init.d/saslauthd start

Some hacker managed to shut it down again and again so eventually I had closed it completely.


Then try to temporarily disable smtpd_sasl_security_options = noanonymous.

Add the postfix user to the sasl group (this makes sure that Postfix has the permission to access saslauthd):

adduser postfix sasl

Then restart Postfix and Saslauthd:

/etc/init.d/postfix restart 
/etc/init.d/saslauthd restart

On servers with systemd, use:

service postfix restart
service saslauthd restart

connect from Sep 30 22:43:18 postfix/smtpd[73064]: warning: SASL authentication failure: cannot connect to saslauthd server: Permission denied Sep 30 22:43:18 postfix/smtpd[73064]: warning: SASL authentication failure: Password verification failed Sep 30 22:43:18 postfix/smtpd[73064]: warning: : SASL PLAIN authentication failed: generic failure Sep 30 22:43:18 postfix/smtpd[73064]: disconnect from ehlo=2 starttls=1 auth=0/1 quit=1 commands=4/5