Email ports
8 email ports: what each one does, its protocol, and whether it is secure by default.
SubnetKit lists 8 email ports, using TCP. 8 of 8 are formally registered with IANA rather than just a widely followed convention.
4 of the 8 email ports are encrypted by default; the rest send data in clear text unless wrapped in TLS, SSH, or a VPN.
Click any port below for its full page: what it does, its protocol, and whether it is safe to expose.
| Port | Service | Protocol | What it does |
|---|---|---|---|
| 25 | SMTP | TCP | Simple Mail Transfer Protocol |
| 109 | POP2 | TCP | Post Office Protocol v2 |
| 110 | POP3 | TCP | Post Office Protocol v3 |
| 143 | IMAP | TCP | Internet Message Access Protocol |
| 465 | SMTPS | TCP | SMTP submission over TLS |
| 587 | Submission | TCP | SMTP mail submission (STARTTLS) |
| 993 | IMAPS | TCP | IMAP over TLS |
| 995 | POP3S | TCP | POP3 over TLS |
Frequently asked questions
Which ports are in the Email category?
port 25 (SMTP), port 109 (POP2), port 110 (POP3), port 143 (IMAP), port 465 (SMTPS), port 587 (Submission), port 993 (IMAPS) and port 995 (POP3S).
How many email ports does SubnetKit list?
8, covering TCP. 8 of them are formally registered with IANA.
Are email ports secure by default?
4 out of 8 are encrypted by default. Check each port's page for its specific encryption status.
Which email port has the lowest number?
Port 25 (SMTP). Port 25 is SMTP, used to relay mail between servers. Many providers block it on residential lines to fight spam; mail clients submit outgoing mail on port 587 or 465 instead.