| Port | Protocol | Description |
|---|---|---|
| 25/tcp | SMTP | Used for communication between servers, for relaying and delivering mails. This connection can be upgraded to an encrypted connection by using STARTTLS |
| 110/tcp | POP3 | |
| 143/tcp | IMAP | |
| 465/tcp | - | Deprecated, never really used, configured like port 25/tcp on some servers |
| 587/tcp | SMTPS | Used by e-mail client |
| 993/tcp | IMAPS | |
| 995/tcp | POP3S |