Email client protocols and port numbers
The port numbers you set determine the protocol your email client uses. There are four basic options. IMAP secure is the recommended configuration:
- IMAP (insecure)
- IMAP (secure)
- POP3 (insecure)
- POP3 (secure)
Below are the settings you can use for each protocol along with the security settings.
Incoming
IMAP | Port 143 (Insecure Transport - No SSL function enabled)
IMAP | Port 993 (Secure Transport - SSL function enabled)
POP3 | Port 110 (Insecure Transport - No SSL function enabled)
POP3 | Port 995 (Secure Transport - SSL function enabled)
Outgoing
SMTP | Port 587 (Insecure Transport - No SSL function enabled)
SMTP | Port 465 (Secure Transport - SSL function enabled)
SMTP | Port 25 (username/password authentication MUST also be enabled!)
Port 587 is a highly recommended alternative port because port 25 is often blocked by ISPs.