Common Network Ports

A reference guide for commonly used network ports and their services.

Port	Protocol	Service	Description	Category	Details
20	TCP	FTP	Used by FTP to transfer files between a client and server.	File Transfer
21	TCP	FTP Control	Used by FTP for control commands to establish and manage the FTP session.	File Transfer
22	TCP	SSH (Secure Shell)	Used for secure remote login and command execution over an encrypted connection.	Remote Access
23	TCP	Telnet	Used for unencrypted remote login and command execution over a network.	Remote Login
55	UDP/TCP	DNS (Domain Resolution)	Used for resolving domain names to IP addresses and vice versa, allowing users to access websites and services using human-readable names instead of numeric IP addresses.	Domain Name System
67	UDP	DHCP (Server to Client)	Used by DHCP servers to assign IP addresses and network configuration to clients on a network.	Dynamic Host Configuration Protocol
68	UDP	DHCP (Client to Server)	Used by DHCP clients to request IP addresses and network configuration from DHCP servers on a network.	Dynamic Host Configuration Protocol
69	UDP	TFTP (Trivial File Transfer Protocol)	Used for simple file transfers without authentication, often in network booting scenarios.	File Transfer
80	TCP	HTTP (Hypertext Transfer Protocol)	Used for unencrypted web traffic, allowing users to access websites and web applications using a web browser.	Web Services
110	TCP	POP3 (Email Receiving)	Used for receiving email from a mail server, allowing users to download their email messages to their local device.	Email Services
123	UDP	NTP (Network Time Protocol)	Used for synchronizing the clocks of computers over a network, ensuring accurate timekeeping across devices.	Time Synchronization
138	UDP	NetBIOS Datagram Service	Provides connectionless communication between NetBIOS devices on a local network. It allows devices to send datagrams, browse network resources, and exchange information without establishing a session.	Network Services
143	TCP	IMAP	Internet Message Access Protocol (IMAP) allows email clients to access and manage messages stored on a mail server without downloading them permanently to a device.	Email Services
161	UDP	SNMP	Simple Network Management Protocol (SNMP) is used to monitor, manage, and collect information from network devices such as routers, switches, servers, printers, and access points.	Network Management
443	TCP	HTTPS	HTTPS (Hypertext Transfer Protocol Secure) provides encrypted communication between a web browser and a web server using SSL/TLS encryption.	Web Services
445	TCP	SMB	Server Message Block (SMB) is a network protocol used for sharing files, folders, printers, and other resources between computers on a network.	File Sharing