Example client settings
SMTP
- host: mail.example.com
- port: 465 (TLS required), 587 alternatively (STARTTLS required)
- authentication required
- username is whole email address username@example.com
Do not use port 25 at all, as it is reserved for remote mail server communication only. Even if it works, you may be subject to unnecessary connection tests and various slowdowns. Some ISPs also block outgoing connections to 25 to combat SPAM, so it may be impossible to connect to your mail server from various locations. Connections to port 465/587 are usually tolerated.
By default, the "From" header is checked → the outgoing email address should be the same as the username. (or you can toggle the check in administration per account)
IMAP (preferred)
- host: mail.example.com
- port: 993
- TLS
- username is whole email address username@example.com
or POP3
- host: mail.example.com
- port: 995
- TLS
- username is whole email address username@example.com