If you, or your clients, are unable to login to your/their email accounts and the system shows this error message:
Plaintext authentication disallowed on non-secure (SSL/TLS) connections
You can verify this error using telnet as follows.
arun@localhost:~$ telnet mail.yourdomain.com 110
Trying xx.xx.xx.xx...
Connected to xx.xx.xx.xx.
Escape character is '^]'.
+OK Dovecot ready.
user test@yourdomain.com
-ERR Plaintext authentication disallowed on non-secure (SSL/TLS) connections.
If you do not want to use SSL/TLS connection to get your email, and to disable SSL/TLS secure connection, do the following:
1. locate dovecot configuration file, dovecot.conf. You can use the following command to locate loaded dovecot.conf.
[root@postfix ~]# doveconf -n | head -n 1
# 2.0.9: /etc/dovecot/dovecot.conf
2. Change the value for this directive from:
disable_plaintext_auth = yes
TO:
disable_plaintext_auth = no
If there is no such entry, you have to add it.
3. Restart dovecot service and verify the settings using telnet.
# /etc/init.d/dovecot restart
arun@localhost:~$ telnet mail.yourdomain.com 110
Trying xx.xx.xx.xx...
Connected to xx.xx.xx.xx.
Escape character is '^]'.
+OK Dovecot ready.
user test@yourdomain.com
+OK
pass testpassword
+OK Logged in.
quit
+OK Logging out.
Connection closed by foreign host.
That's it...
