Port Number Reference
Quick Answer
A port number identifies a specific process or service on a host. Combined with an IP address, it uniquely identifies a network connection endpoint.
What Is Port Number Reference?
Port Number Reference is a free online network tools tool that look up tcp and udp port numbers and their associated services. A port reference lists the most common TCP and UDP port numbers used on the internet, grouped by category: web (80, 443), email (25, 587, 993), SSH (22), FTP (21), databases (3306, 5432, 27017), and more. Each entry shows the port number, the protocol (TCP, UDP, or both), the service name, and a brief description. This is a quick lookup for developers configuring firewalls, debugging connection issues, or studying network fundamentals. You can search by port number or by service name. The reference covers the well-known ports (0–1023) and some commonly used registered ports (1024–49151). The data is static and client-side. Unlike many similar tools, it runs entirely in your browser — no data is sent to any server, no account is required, and there are no usage limits. Whether you are a developer, writer, SEO professional, or casual user, this tool provides instant, accurate results without friction.
How to Use Port Number Reference
Search by port number (e.g. 443) or service name (e.g. 'mysql'). The reference filters as you type. Click any entry for more details.
Key Features
- Search by port or service name
- Coverage of well-known and common registered ports
- Protocol (TCP/UDP) and service description
- Fully client-side
Common Use Cases
- Checking what service runs on a port during firewall configuration
- Debugging why a service is not listening on the expected port
- Studying for networking or security certifications
Common Mistakes to Avoid
- Confusing TCP and UDP for a given service — some services use both
- Assuming a port is always associated with one service (port 8080 is often HTTP-alt but could be anything)
- Forgetting that ports above 1024 can be used by any user-level process
Related Topics & Entities
- TCP
- UDP
- Port number
- IANA
- Firewall
Common Questions About Port Number Reference
Related Tools & Resources
- HTTP Status Codes
- IP Lookup
- SSL Checker
Best Practices for Port Number Reference
To get the most out of Port Number Reference, follow these best practices. Ensure your input data is clean and properly formatted for the most accurate results. Use the copy function to transfer output directly to your clipboard. Bookmark the tool for easy access. Check the related tools section below for complementary utilities that can enhance your workflow. Remember that all processing is client-side, so your data never leaves your browser.
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Privacy & Security
Port Number Reference processes all data entirely within your browser using JavaScript. No text, files, or personal information is transmitted to any server. Your data stays on your device, making this tool safe for sensitive content. We do not track usage, store inputs, or share data with third parties. The tool works offline after the initial page load and requires no account to use.
Frequently Asked Questions
Find answers to common questions about this tool.