A guide to common network ports
Network ports are virtual points through which computer applications exchange data over a network. Every popular service, whether a website, email client, or remote access server, is assigned its own standard port. This reference provides structured information about the most important and frequently used ports, their purposes, and functions. Knowing these ports is essential for understanding the internet, configuring network equipment, and ensuring security.
21 - File Transfer (FTP)
Port 21 is the control port for the File Transfer Protocol (FTP). It is used to establish a connection and transmit commands between the client and server, while the files themselves are transferred over a separate data connection.
22 - Secure Remote Management (SSH)
Port 22 is used for the Secure Shell (SSH) protocol, which enables secure remote management of servers and network devices. It encrypts all communication sessions, including logins and file transfers, providing a secure alternative to insecure protocols like Telnet.
23 - Legacy Remote Management (Telnet)
Port 23 is associated with the Telnet protocol, which is used for remote management of network devices. Unlike SSH, Telnet does not provide encryption, making all data (including passwords) vulnerable to interception. Its use is currently considered insecure.
25 - Sending Email (SMTP)
Port 25 is used by the SMTP (Simple Mail Transfer Protocol) protocol for transferring outgoing email between mail servers. It is not typically used by clients (such as Outlook) to send emails; this role is taken over by ports 587 and 465.
53 - Domain Name System (DNS)
Port 53 is used by the Domain Name System (DNS), which translates human-readable website addresses (e.g., google.com) into machine IP addresses (e.g., 142.251.132.46). Without this port, we would not be able to find websites by their names.
80 - Standard HTTP Web Traffic
Port 80 is used to transmit unencrypted web traffic over HTTP. This is the standard port for normal website browsing where data privacy is not critical. All traffic, including passwords, is transmitted in cleartext.
110 - Email Retrieval (POP3)
Port 110 is used by the POP3 (Post Office Protocol version 3) protocol to download emails from the mail server to the client"s local computer. After downloading, the emails are typically deleted from the server.
143 - Mailbox Access on the Server (IMAP)
Port 143 is used by the IMAP (Internet Message Access Protocol) protocol, which allows you to manage email directly on the mail server. This enables synchronization of emails and folders between multiple clients (e.g., a phone and a computer).
443 - Secure Web Connection Traffic (HTTPS)
Port 443 is used for secure web traffic (HTTPS), encrypting data during transmission between the user"s browser and the web server using SSL/TLS protocols. It is used to protect sensitive information, such as banking information, passwords, and personal data, making online communication secure.
587 - Secure Mail Submission from the Client (SMTP Submission)
Port 587 is the modern standard for sending email from email clients (MUAs - Mail User Agents) to the server. It requires authentication and uses encryption (STARTTLS), making it more secure for users.
993 - Secure Mail Access via IMAP (IMAPS)
Port 993 provides a secure version of IMAP, where the connection between the client and server is encrypted with SSL/TLS from the start. This is the standard port for secure mailbox access.
995 - Secure Mail Retrieval via POP3 (POP3S)
Port 995 provides a secure version of POP3, where the connection between the client and server is encrypted with SSL/TLS. This is the standard port for securely downloading emails to your local device.
3306 - MySQL Database
Port 3306 is the default port for MySQL database servers. It is used by client applications to connect to and manage MySQL databases.
3389 - Remote Desktop (RDP)
Port 3389 is used by the RDP (Remote Desktop Protocol), developed by Microsoft. It allows users to connect to a remote computer"s graphical desktop and work with it as if they were sitting directly at it.
5432 - PostgreSQL Database
Port 5432 is the default port for PostgreSQL database management systems. Clients use it to communicate with the database server to execute queries.