In order for the communication between the users and the mail server to be secure and encrypted, once you make sure that your applications and operating system are compatible with TLS version v1.2 and above, you should use :

    1. Secure ports using SSL / TLS communication protocol.

    2. Encrypted password

Therefore, we recommend that you use:

IMAP: Secure port: 993, using SSL / TLS

POP3: Secure port: 995, using SSL / TLS

SMTP: Secure port: 465, using SSL / TLS

Important:

In case you use secure ports (993, 995, 465) with SSL / TLS communication protocol, then no further action is required in regards to encrypted password.

NOTE:

If for some reason, any of the secure ports recommended above cannot be used (e.g. due to a firewall), you can use the default ports 143, 110 & 25 or 587 as an alternative, while using STARTTLS and encrypted password. This upgrades the connection from insecure to secure, if it is supported by the client and the server. A prerequisite, as mentioned above, is that your applications and operating systems support TLS v1.2 and above.

IMAP: Insecure port: 143, using STARTTLS

POP3: Insecure port: 110, using STARTTLS

SMTP: Insecure port: 25 or 587, using STARTTLS

Important:

Ιf you are using the default ports (143, 110 & 25 or 587) as well as STARTTLS, then in the authentication method you should select encrypted password, if for any reason the communication is not encrypted, the password will still be encrypted and won’t look like plain text.