Well-Known Network Ports CheatSheet

Well-Known Network Ports

Network Ports Cheatsheet

IT Professional Reference

Network Ports Cheatsheet

Complete list of TCP, UDP & SCTP port numbers — well-known, registered & dynamic ports with security ratings for network engineers, sysadmins & IT professionals.

205

Total Ports

77

Well-Known

127

Registered

1

Dynamic

📖 Port Range & Protocol Reference Documentation

Port ranges, transport protocols, app protocols & quick-reference cards — available at the bottom ↓

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Port Range & Protocol Reference

Complete documentation on port ranges, transport layers, and common application protocols

Port Range Reference

Well-known / System Ports

Reserved for system services and well-known protocols

Range: 0 – 1,023

Assigned by IANA and used by core OS services and widely adopted network protocols. Access to these ports typically requires administrative (root) privileges on the host system.

77 ports available

Registered Ports

Assigned by IANA for specific applications and services

Range: 1,024 – 49,151

Registered with IANA for specific applications. No root privileges required. Commonly used by databases, enterprise apps, game servers, and user-installed services.

127 ports available

Dynamic / Private Ports

Available for dynamic allocation and private applications

Range: 49,152 – 65,535

Also known as ephemeral ports, these are dynamically assigned by the OS for temporary client-side connections. Not registered with IANA for any specific service.

1 port available

Protocol Categories Explained — Transport Protocols

TCP

Transmission Control Protocol

Reliable, connection-oriented protocol ensuring data delivery and order. Uses a three-way handshake. Ideal for web, email, file transfers, and any use case where data integrity matters.

UDP

User Datagram Protocol

Fast, connectionless protocol for real-time applications and streaming. No delivery guarantee or ordering, but very low latency. Ideal for DNS, VoIP, video streaming, and online gaming.

SCTP

Stream Control Transmission Protocol

Advanced protocol combining TCP reliability with UDP performance. Supports multi-homing and multi-streaming. Widely used in telephony signalling (SS7/SIGTRAN) and telecom infrastructure.

Common Application Protocols

HTTP/S

HTTP / HTTPS — Web Traffic

Standard web protocols for browsing and API communications. HTTP (port 80) is unencrypted; HTTPS (port 443) uses TLS/SSL encryption. Always prefer HTTPS for sensitive or authenticated interactions.

SMTP

SMTP / POP3 / IMAP — Email

Email protocols for sending, receiving, and managing messages. SMTP (25/587) sends mail; POP3 (110/995) retrieves it; IMAP (143/993) syncs across devices. Secure variants use TLS/SSL encryption.

SSH

SSH / Telnet — Remote Access

Remote terminal access protocols. SSH (port 22) provides encrypted, authenticated access and is the industry standard. Telnet (port 23) is unencrypted and transmits credentials in plaintext — avoid in production.

Quick Reference for IT Professionals

22

SSH

Secure Remote Access

443

HTTPS

Secure Web Traffic

3389

RDP

Remote Desktop

3306

MySQL

Database Server

53

DNS

Domain Name System

80

HTTP

Web Traffic

25

SMTP

Mail Transfer

5432

PostgreSQL

Database Server

Frequently Asked Questions — Network Ports

What are well-known network ports (0–1023)?

Well-known ports range from 0 to 1,023 and are assigned by IANA for core OS services and widely adopted protocols. Examples include HTTP (80), HTTPS (443), SSH (22), FTP (21), DNS (53), SMTP (25), and Telnet (23). Access typically requires root or administrative privileges on the host system.

What is the difference between TCP and UDP ports?

TCP (Transmission Control Protocol) is connection-oriented and guarantees reliable, ordered delivery via a three-way handshake — used for HTTP, HTTPS, SSH, FTP, and email. UDP (User Datagram Protocol) is connectionless with no delivery guarantee, offering lower latency — ideal for DNS, VoIP, video streaming, and online gaming.

What port does SSH use?

SSH (Secure Shell) uses TCP port 22 by default. It provides encrypted, authenticated remote terminal access and secure file transfers (SCP/SFTP). It replaces the insecure Telnet protocol (port 23), which transmits credentials in plaintext.

What port does HTTPS use?

HTTPS (HTTP over TLS/SSL) uses TCP port 443. It encrypts web traffic using TLS certificates. Plain HTTP uses port 80 but is unencrypted and should be avoided for any authenticated or sensitive interactions.

What port does RDP use?

RDP (Remote Desktop Protocol) uses TCP port 3389 for remote GUI access to Windows systems. Because it is a frequent attack target, best practice is to restrict access using a VPN or firewall, or change the default port and enable Network Level Authentication (NLA).

What are registered ports (1024–49151)?

Registered ports range from 1,024 to 49,151 and are registered with IANA for specific applications — no root privileges required. Common examples include MySQL (3306), PostgreSQL (5432), MongoDB (27017), RDP (3389), Redis (6379), and OpenVPN (1194).

What are dynamic / ephemeral ports?

Dynamic ports (also called ephemeral ports) range from 49,152 to 65,535. They are assigned by the OS for temporary client-side outbound connections and are not registered with IANA for any specific service. They are automatically released when the connection closes.

What port does DNS use?

DNS (Domain Name System) uses both TCP and UDP port 53. UDP handles standard queries; TCP handles larger responses and zone transfers. DNS over HTTPS (DoH) uses port 443, and DNS over TLS (DoT) uses port 853.

Related Topics

TCP Port NumbersUDP Port NumbersSCTP Ports Well-Known Ports ListRegistered PortsEphemeral Ports Firewall Port ReferenceIANA Port RegistryNetwork Security Ports SSH Port 22HTTP Port 80HTTPS Port 443 DNS Port 53FTP Port 21SMTP Port 25 RDP Port 3389MySQL Port 3306PostgreSQL Port 5432 MongoDB Port 27017Redis Port 6379OpenVPN Port 1194 Sysadmin CheatsheetNetwork Engineer ReferenceIT Professional Tools

Network Ports Cheatsheet — Covering 205+ TCP, UDP & SCTP ports across well-known (0–1,023), registered (1,024–49,151), and dynamic (49,152–65,535) ranges. Data sourced from the IANA Service Name and Transport Protocol Port Number Registry. Updated 2025.