Search by port number or by service. Covers the well-known and commonly-registered ports you actually meet in firewall rules, scans, and captures — entirely offline.
| Port | Proto | Service | Description |
|---|
TCP and UDP port numbers run 0–65535, split by IANA into three ranges: well-known (0–1023), registered (1024–49151), and dynamic/ephemeral (49152–65535). Servers listen on well-known or registered ports; clients source from the ephemeral range.
A port number alone doesn't guarantee a service — anything can listen anywhere — but the conventional assignments below are what firewalls, scanners, and IDS signatures expect. Note that the same number can mean different things over TCP vs UDP (for example, 53 DNS uses both).
Seeing an unexpected listener on a well-known port (say 23/telnet or 3389/rdp exposed to the internet) is exactly the kind of thing this reference helps you flag quickly.
443/tcp. Plain HTTP is 80/tcp, and HTTP/3 (QUIC) is 443/udp.
Well-known ports (0–1023) are reserved for standard services and typically need elevated privileges to bind. Ephemeral ports (49152–65535) are assigned temporarily to client connections.
Absolutely. The assignments are conventions, not guarantees. Always verify what's actually listening.