What is a port number?

A port is a 16-bit number (0–65535) used by the TCP and UDP transport protocols to direct traffic to the correct application or service on a host. Different services listen on different ports: for example, web servers typically listen on port 80 (HTTP) or 443 (HTTPS).

What is the difference between TCP and UDP ports?

TCP (Transmission Control Protocol) provides reliable, ordered, connection-oriented communication. UDP (User Datagram Protocol) is connectionless and faster but without delivery guarantees. Many services use TCP, while real-time applications like DNS, video streaming, and VoIP often use UDP.

What are well-known ports?

Well-known ports are the range 0–1023. They are assigned by IANA to widely-used internet services: for example, port 22 (SSH), port 25 (SMTP), port 80 (HTTP), and port 443 (HTTPS). Administrative privileges are typically required to bind to these ports.

What are registered ports?

Registered ports are the range 1024–49151. They are registered with IANA for specific services but do not require administrative privileges to use. Common examples include port 3306 (MySQL), port 5432 (PostgreSQL), and port 8080 (alternative HTTP).

What are dynamic or ephemeral ports?

Ports 49152–65535 are dynamic or ephemeral ports. They are not assigned to specific services and are used by operating systems as temporary source ports for outbound connections.

Why does knowing port numbers matter?

Understanding ports is essential for configuring firewalls and security groups, setting up network services, troubleshooting connectivity issues, reading network logs, and hardening server security by closing unused ports.

Can a port run both TCP and UDP?

Yes. Some services use the same port number for both protocols. DNS, for example, uses port 53 for both TCP and UDP. The protocol used depends on the query type and response size.

Yes, completely free with no account, no sign-up, and no usage limits.

Browser Info User Agent Parser Color Converter Unit Converter Timezone Converter HTTP Status Codes MIME Types Cron Expression Keyboard Tester Character Map IP Subnet Calculator Port Reference Device Test Bulk URL Opener What is My IP WHOIS Lookup Page Speed Analyzer Broken Link Checker Canonical Tag Checker

Port Numbers Reference

Searchable reference of well-known TCP/UDP port numbers for common services.

Quick Port Lookup

Showing 67 of 67 ports

TCP and UDP ports reference: searchable directory of well-known and registered ports

Ports are the addressing mechanism that allows a single host to run multiple network services simultaneously. Knowing which ports are used by which services is essential for network engineers, system administrators, security professionals, and developers working with firewalls, load balancers, or cloud security groups. This reference covers the IANA well-known and registered port assignments plus the most commonly encountered application ports.

Search by port number or service name and filter by TCP or UDP to find exactly what you need. Each entry includes the official service name, the transport protocol, and a plain-English description of what the service does.

Step-by-step guide

1
Search by port number or service name
Type a port number (e.g. 443) or a service name (e.g. HTTPS, SSH, FTP) to filter the list instantly.
2
Filter by protocol
Use the TCP/UDP filter to narrow results to a specific transport protocol if you know which one applies.
3
View the service description
Each port entry shows the official service name, the protocol (TCP, UDP, or both), and a description of what the service does.
4
Check well-known vs registered vs dynamic ranges
The port table is organised to help you understand which range (0–1023 well-known, 1024–49151 registered, 49152–65535 dynamic) a port falls in.
5
Copy the port number
Click Copy to put the port number on your clipboard for use in firewall rules, server configuration, or documentation.

Related Tools

🌐

Browser Info

Inspect your browser, OS, screen, network, and feature support in real time. Hardware concurrency, touch points, WebGL, WASM, and 18 more APIs checked.

🔍

User Agent Parser

Parse any user agent string into browser, engine, OS, device type, and bot detection. Test with 6 sample UAs or paste your own.

🎨

Color Converter

Convert colors between HEX, RGB, HSL, HSV, and CMYK instantly. Visual swatch, color picker, named color lookup, and WCAG contrast ratio.

📏

Unit Converter

Convert between units across 7 categories: length, weight, temperature, area, volume, speed, and digital storage. All conversions shown simultaneously.

Frequently Asked Questions

What is a port number?: A port is a 16-bit number (0–65535) used by the TCP and UDP transport protocols to direct traffic to the correct application or service on a host. Different services listen on different ports: for example, web servers typically listen on port 80 (HTTP) or 443 (HTTPS).
What is the difference between TCP and UDP ports?: TCP (Transmission Control Protocol) provides reliable, ordered, connection-oriented communication. UDP (User Datagram Protocol) is connectionless and faster but without delivery guarantees. Many services use TCP, while real-time applications like DNS, video streaming, and VoIP often use UDP.
What are well-known ports?: Well-known ports are the range 0–1023. They are assigned by IANA to widely-used internet services: for example, port 22 (SSH), port 25 (SMTP), port 80 (HTTP), and port 443 (HTTPS). Administrative privileges are typically required to bind to these ports.
What are registered ports?: Registered ports are the range 1024–49151. They are registered with IANA for specific services but do not require administrative privileges to use. Common examples include port 3306 (MySQL), port 5432 (PostgreSQL), and port 8080 (alternative HTTP).
What are dynamic or ephemeral ports?: Ports 49152–65535 are dynamic or ephemeral ports. They are not assigned to specific services and are used by operating systems as temporary source ports for outbound connections.
Why does knowing port numbers matter?: Understanding ports is essential for configuring firewalls and security groups, setting up network services, troubleshooting connectivity issues, reading network logs, and hardening server security by closing unused ports.
Can a port run both TCP and UDP?: Yes. Some services use the same port number for both protocols. DNS, for example, uses port 53 for both TCP and UDP. The protocol used depends on the query type and response size.
Is this tool free?: Yes, completely free with no account, no sign-up, and no usage limits.

AlteredIdea vs alternatives

vs server-side converters: AlteredIdea converts in your browser: your data never leaves your device.

vs writing scripts: Instant results, no coding needed.

vs paid tools: Completely free, no account required.

Share:Share on X Share on LinkedIn