TCP/UDP Port Number Lookup
Search common TCP/UDP ports for their standard use, security risks, and diagnostic commands
Look up what any common TCP/UDP port is officially used for according to IANA, along with its service name. Each entry flags the security risks of leaving that port exposed and gives you copy-paste CLI commands for testing whether it's open.
도구를 불러오는 중…
🔒 Everything runs 100% in your browser. Your files and input are never uploaded to any server.
How to use
- Search by port number (e.g. 80, 22) or by service name (ssh, mysql, web).
- Narrow the list with the category filters — Web, Remote Access, Database, Mail, and more.
- Read the description and security warnings for each port, then copy the diagnostic commands (nc, lsof) at the bottom.
FAQ
- What's the difference between system and registered ports?
- Ports 0–1023 are the "well-known" ports, reserved for the OS and core infrastructure services. Ports 1024–49151 are "registered" ports, claimed by specific applications such as databases.
- How do I check whether a port is open on a remote host?
- Run netcat from your terminal: nc -zv <IP address> <port>. Telnet works as a quick alternative for checking whether the remote socket accepts a connection.
- If two services share the same port number, are TCP and UDP treated separately?
- Yes — TCP and UDP ports live in entirely separate number spaces. Port 53, for instance, is used for DNS on both, but plenty of services only listen on one protocol at that number and not the other, so you need to check TCP and UDP status independently.