Port Number Lookup
Look up what service runs on any TCP or UDP port, or find the port a service uses.
Port 443
- IANA range
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- Privileged on Unix
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- Hexadecimal
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- Known services
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| Port | Protocol | Service | Description | Category |
|---|
How it works
Type a port number to see what normally listens there, or type a service name like
ssh, postgres or rdp to find the port it uses.
Every result shows the transport protocol (TCP, UDP or both), the service name, a plain-English
description and a category, and you can narrow the list by protocol or category. When you search
a number, the card above the table also classifies it using the IANA/RFC 6335 ranges:
0–1023 are system (well-known) ports, 1024–49151 are registered
(user) ports, and 49152–65535 are dynamic/private ports that operating systems
hand out as ephemeral source ports. Ports below 1024 are privileged on Unix-like systems, so
binding to them normally needs root or a capability such as CAP_NET_BIND_SERVICE.
The dataset is a curated list of roughly 200 of the ports you actually meet in firewall rules, scan output and server configs — not the full IANA registry, which holds many thousands of mostly unused assignments. Anything can of course be configured to listen on any port, so treat this as a fast reference rather than proof of what a given host is running. The whole list is embedded in this page: the lookup runs entirely in your browser with plain JavaScript, nothing is sent to a server, and what you search for is never logged. Copy the visible results as text or export them as CSV without leaving the page.
Frequently asked questions
What are the well-known, registered and dynamic port ranges?
IANA and RFC 6335 split the 16-bit port space into three ranges: 0–1023 are system or well-known ports (HTTP, SSH, DNS and friends), 1024–49151 are registered or user ports assigned to specific applications, and 49152–65535 are dynamic or private ports that operating systems hand out as ephemeral source ports. This tool shows which range a port falls into as soon as you type a number.
Why do ports below 1024 need root on Linux and macOS?
Unix-like systems treat ports 0–1023 as privileged: only a process running as root, or one granted the CAP_NET_BIND_SERVICE capability, can bind to them. It stops an ordinary user from impersonating a system service such as a web server on port 80. That is why apps often run on 8080 or 3000 in development and sit behind a reverse proxy in production.
Does this tool scan my computer or network?
No. It is a reference lookup, not a port scanner. The whole port list is embedded in the page and the search runs on plain JavaScript in your browser, so nothing is sent to a server and what you type is never logged. It also cannot prove what a given host is running: any application can be configured to listen on any port, so treat the results as the conventional assignment rather than a guarantee.