Issue Cannot send mail using None encryption on SMTP in Plesk Onyx 17.5

[Joe Gubat]

I have plesk 12.5 and migrated all accounts to plesk onyx 17.5.3. On plesk 12.5, I have no issue in sending on all type SSL/TLS, Auto and None encryption using port 587. However, when I migrated to plesk onyx 17.5.3 I cannot use none anymore. Is there any possibility I can still use None, Auto and SSL/TLS (all of them) just like on my old plesk?

 

[Émerson Felinto]

Is this Plesk Onyx 17.5 on another server or did you update Plesk?

Already checked the log? What does he say ?

tail -f /var/log/maillog

 

[Joe Gubat]

Below is a sample maillog using port 587 with None encryption:
Mar 11 06:58:36 server dovecot: pop3-login: Login: user=<james@blank.com>, method=DIGEST-MD5, rip=112.200.103.222, lip=172.31.222.21, mpid=28260, TLS, session=<GO7sjR1nBjdwyGfT>
Mar 11 06:58:36 server dovecot: service=pop3, user=james@blank.com, ip=[112.200.103.222]. Disconnected: Logged out rcvd=12, sent=50, top=0/0, retr=0/0, del=0/45, size=6359449
Mar 11 06:58:37 server postfix/smtpd[29732]: warning: hostname 112.200.103.222.pldt.net does not resolve to address 112.200.103.222: Name or service not known
Mar 11 06:58:37 server postfix/smtpd[29732]: connect from unknown[112.200.103.222]
Mar 11 06:58:37 server postfix/smtpd[29732]: lost connection after EHLO from unknown[112.200.103.222]
Mar 11 06:58:37 server postfix/smtpd[29732]: disconnect from unknown[112.200.103.222] ehlo=1 commands=1
Mar 11 06:59:29 server dovecot: pop3-login: Login: user=<james@blank.com>, method=DIGEST-MD5, rip=112.200.103.222, lip=172.31.222.21, mpid=3088, TLS, session=<IesRkR1nIDdwyGfT>
Mar 11 06:59:29 server dovecot: service=pop3, user=james@blank.com, ip=[112.200.103.222]. Disconnected: Logged out rcvd=12, sent=50, top=0/0, retr=0/0, del=0/45, size=6359449
Mar 11 06:59:29 server postfix/smtpd[29732]: warning: hostname 112.200.103.222.pldt.net does not resolve to address 112.200.103.222: Name or service not known
Mar 11 06:59:29 server postfix/smtpd[29732]: connect from unknown[112.200.103.222]
Mar 11 06:59:30 server postfix/smtpd[29732]: lost connection after EHLO from unknown[112.200.103.222]
Mar 11 06:59:30 server postfix/smtpd[29732]: disconnect from unknown[112.200.103.222] ehlo=1 commands=1

 

[MarkM]

What is the message size? Are you sending an attachment? An immediate disconnection could be due to exceeding the message_size_limit in Postfix.

 

[Émerson Felinto]

Exact!

You can increase the attachment limit size by adding the following line to the file "/etc/postfix/main.cf".

message_size_limit = 20480000

Source: Solved: postfix lost connection after EHLO on RHEL7 | SysArchitects

Maybe you're still in trouble ...

Try to follow the same steps again and this time send a file without attachment and post the output of the command "tail -f /var/log/maillog"...

 

[Joe Gubat]

it is just a test from outlook.

 

[Bitpalast]

You may want to look at this article for a solution: TLS encryption in Plesk with Postfix 2.8