Published: February 19, 2022

Last Modified: April 5, 2023


Ports are a kind of subaddress. The IP address is the primary address and the port is the subaddress. Think of the IP address as the street address of a building and then the port as the apartment number. I need the street address to get to the right building, but I need the apartment address to find who I am looking for. This is the same with ports. The IP address gets us to right machine, but the port takes us to correct service, say HTTP on port 80.
๐Ÿ’  There are 65,536 ports. The first 1,024 are generally referred to as the common ports. People obviously don’t remember all 65,536 ports (unless they are savant), or even the 1,024 most common ports. As a hacker, there are a few ports that you should know by heart:
๐Ÿ”น 20 FTP
๐Ÿ”น 21 FTP
๐Ÿ”น 22 SSH
๐Ÿ”น 23 Telnet
๐Ÿ”น 25 SMTP
๐Ÿ”น 53 DNS
๐Ÿ”น 69 TFTP
๐Ÿ”น 80 HTTP
๐Ÿ”น 443 HTTPS or HTTP over SSL
๐Ÿ”น 3389 RDP
I will cover subnetting, IPv6, TCP/IP, and more on our channel soon..

Theย Internet Assigned Numbers Authorityย (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 portsย can help you work more efficiently.

What ports do you use the most, and why?

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