Look up any network port instantly. Search by port number, service name, or keyword. Filter by category (Database, Web, DevOps) or risk level (Critical, High, Medium, Low) to find exactly what you need.
Search: Type a port number (e.g., 443), service name (e.g., "Redis"), or keyword (e.g., "encryption" or "EternalBlue") in the search bar. Results update instantly.
Quick ports: Click any of the common port buttons (:22, :80, :443, etc.) to jump directly to that port's details.
Filter by category: Click the Filters button to show category chips (Web, Database, DevOps, Remote Access, etc.) and risk level chips (Critical, High, Medium, Low). Multiple filters combine additively.
Read security notes: Ports with amber warning badges include actionable security guidance — why the port is risky and what to use instead.
Copy details: Hover over any port card and click the copy button to get a formatted text summary for documentation or chat.
About This Tool
Port Ranges and IANA Assignments
The Internet Assigned Numbers Authority (IANA) divides the 65,535 available port numbers into three ranges. Well-known ports (0-1023) are assigned to standard protocols like HTTP, SSH, and DNS. Registered ports (1024-49151) are assigned to specific applications like MySQL (3306), PostgreSQL (5432), and MongoDB (27017). Dynamic/ephemeral ports (49152-65535) are used temporarily by client-side connections and are not assigned to any service.
Security Risk Ratings
Each port is assigned a risk level based on its real-world attack surface. Critical ports (red) are those with well-documented exploits and should never be exposed to the internet — including FTP (21), Telnet (23), SMB (445), RDP (3389), and unauthenticated databases like Redis (6379). High risk ports transmit data unencrypted or lack default authentication. Medium risk ports are secure but commonly targeted. Low risk ports use encryption by default and have strong authentication.
TCP vs UDP Protocols
TCP provides reliable, ordered delivery through a three-way handshake (SYN, SYN-ACK, ACK), making it suitable for web traffic, file transfers, and database connections. UDP is connectionless — packets are sent without confirmation, making it faster but unreliable. This tradeoff makes UDP ideal for DNS queries, VoIP, video streaming, and gaming where speed matters more than guaranteed delivery. Some services use both: DNS uses UDP for standard queries but falls back to TCP for responses larger than 512 bytes or zone transfers.
Firewall Best Practices
The principle of least privilege applies directly to port management: only open ports that are actively needed, and restrict access by source IP where possible. Default-deny firewall rules (block everything, then allow specific ports) are more secure than default-allow rules. Internal services like databases (3306, 5432, 27017), caching (6379, 11211), and container orchestration (2375, 6443, 10250) should never be directly accessible from the internet — use VPN tunnels, SSH port forwarding, or private networks instead.
Why Use This Tool
Security-First Reference
Most port lists show a service name and nothing else. This reference includes security risk ratings, protocol details, and actionable notes explaining why a port is dangerous and what to do about it. Whether you're reviewing nmap scan results, configuring a firewall, or studying for a network certification, every entry gives you context that a bare service name cannot.
Filter by category to focus on database ports, DevOps infrastructure, or remote access tools. Filter by risk level to prioritize your security audit. Everything runs 100% client-side — your search queries never leave your browser.
FAQ
What are well-known ports and why do they matter?
Well-known ports (0-1023) are assigned by IANA to standard services like HTTP (80), HTTPS (443), and SSH (22). They matter because firewalls and security policies are built around them — knowing which port a service uses is essential for network configuration, security auditing, and troubleshooting.
Which network ports are the most dangerous to leave open?
The most critical ports to protect include: 21 (FTP — cleartext passwords), 23 (Telnet — no encryption), 135 (MS-RPC — Windows attack surface), 445 (SMB — WannaCry/EternalBlue), 3389 (RDP — ransomware target), 6379 (Redis — no auth by default), and 27017 (MongoDB — historically no auth). Never expose these directly to the internet.
What is the difference between TCP and UDP ports?
TCP (Transmission Control Protocol) provides reliable, ordered delivery with connection setup via a three-way handshake — used by HTTP, SSH, and databases. UDP (User Datagram Protocol) is connectionless and faster but unreliable — used by DNS queries, VoIP, gaming, and streaming. Some services like DNS use both: UDP for queries and TCP for zone transfers.
How do I use this tool to audit my network security?
Search for ports found in your scan results (e.g., nmap output) to identify each service and its risk level. Filter by 'Critical' or 'High' risk to see which ports need immediate attention. The security notes explain why specific ports are dangerous and recommend safer alternatives.