Port Number Lookup
Look up TCP/UDP port assignments — 443 HTTPS, 5432 Postgres — with service context. Identify mystery listeners instantly — local reference, free, no signup.
How to Use the Port Number Lookup
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Frequently Asked Questions
What runs on 5432?
PostgreSQL by default — seeing it listening means a database accepts connections. Verify it's bound to localhost, not 0.0.0.0, on workstations.
Well-known vs registered?
0–1023 well-known (HTTP 80, HTTPS 443, SSH 22) need privileges; 1024–49151 registered (Postgres 5432, Redis 6379); 49152+ ephemeral for outbound.
Unknown port listening?
Check the owning process (netstat/ss) before assuming malware — dev servers, updaters, and sync tools all listen legitimately.
Do lookup queries upload?
No — lookup runs against a local reference in your browser. Nothing leaves your device.
How big is the table, and what inputs are rejected?
24 named ports from 20 (FTP Data) to 27017 (MongoDB); the box defaults to 443. Anything below 1 or above 65535 returns Invalid port number (1-65535); categories cut at 1024 (Well-known below) and 49152 (Registered below, Dynamic/Private at and above).
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Last updated October 2026