The Internet Assigned Numbers Authority (IANA) has assigned port numbers to commonly used services like SSH, FTP, HTTP, HTTPS, and others. Here are some of the most common ones:
Port Number | Usage |
20 | File Transfer Protocol (FTP) Data Transfer |
21 | File Transfer Protocol (FTP) Command Control |
22 | Secure Shell (SSH) |
23 | Telnet - Remote login service, unencrypted text messages |
25 | Simple Mail Transfer Protocol (SMTP) E-mail Routing |
53 | Domain Name System (DNS) service |
80 | Hypertext Transfer Protocol (HTTP) used in World Wide Web |
110 | Post Office Protocol (POP3) used by e-mail clients to retrieve e-mail from a server |
119 | Network News Transfer Protocol (NNTP) |
123 | Network Time Protocol (NTP) |
143 | Internet Message Access Protocol (IMAP) Management of Digital Mail |
161 | Simple Network Management Protocol (SNMP) |
194 | Internet Relay Chat (IRC) |
443 | HTTP Secure (HTTPS) HTTP over TLS/SSL |
In my work, I most commonly come across ports 80, 443, 20, 21, 22, 23, 25, and 53. Knowing these ports can help you work more efficiently.
What ports do you use the most, and why?