This is a list of common ports for reference.
| Port | Protocol |
|---|---|
| 20 | FTP data (File Transfer Protocol) |
| 21 | FTP (File Transfer Protocol) |
| 22 | SSH (Secure Shell) |
| 23 | Telnet |
| 25 | SMTP (Send Mail Transfer Protocol) |
| 43 | whois |
| 53 | DNS (Domain Name Service) |
| 68 | DHCP (Dynamic Host Control Protocol) |
| 79 | Finger |
| 80 | HTTP (HyperText Transfer Protocol) |
| 110 | POP3 (Post Office Protocol, version 3) |
| 115 | SFTP (Secure File Transfer Protocol) |
| 119 | NNTP (Network New Transfer Protocol) |
| 123 | NTP (Network Time Protocol) |
| 137 | NetBIOS-ns |
| 138 | NetBIOS-dgm |
| 139 | NetBIOS |
| 143 | IMAP (Internet Message Access Protocol) |
| 161 | SNMP (Simple Network Management Protocol) |
| 194 | IRC (Internet Relay Chat) |
| 220 | IMAP3 (Internet Message Access Protocol 3) |
| 389 | LDAP (Lightweight Directory Access Protocol) |
| 443 | SSL (Secure Socket Layer) |
| 445 | SMB (NetBIOS over TCP) |