| Port | Use | |
| 25 | smtp, can run plain text email and starttls | |
| 26 | smtp, can run plain text email and starttls, also used by email companies when port 25 is blocked | |
| 110 | pop3 plain text | |
| 143 | imap plain text | |
| 465 | smtp Enforced SSL/TLS | |
| 587 | smtp can run plain text email and starttls - supposed to be the standard port for enforced TLS encyption. cPanel allows StartTLS and plain text on this port by default. | |
| 993 | pop3 secure (SSL/TLS) | |
| 995 | imap secure (SSL/TLS) | |
| 2525 | smtp unofficial alternative |
* starttls allows a plain text session to upgrade to TLS