Port numbers reference
Search by port number, service name or keyword, and filter by TCP or UDP. The list covers the widely used assignments from the IANA Service Name and Transport Protocol Port Number Registry, from echo on port 7 to HTTPS on 443 and databases such as MySQL on 3306.
Runs in your browser: nothing you enter is sent anywhere.
How to use it
- Type a port number (
443), a service name (postgres) or a word from the notes (mail). Several words must all match.
- Use the TCP and UDP buttons to narrow the list.
- If you type a number, the tool also says which range it falls in.
How ports work
An IP address names a machine and a port number names a service on it. A connection is identified by the addresses and ports on both ends, and the transport is TCP or UDP. A server listens on a fixed port so that clients know where to connect; the client uses a temporary dynamic port for its end.
Tips
- A web address without a port uses 80 for http and 443 for https.
- Opening ports in a firewall is a security decision: expose only what you need and prefer encrypted variants such as SSH, IMAPS and HTTPS over Telnet, IMAP and HTTP.
Frequently asked questions
What are well-known, registered and dynamic ports?
RFC 6335 splits the 65,536 ports into three ranges. System ports 0–1023 (the well-known ports) are assigned by IANA to standard services. User ports 1024–49151 can be registered for applications. Ports 49152–65535 are dynamic or private and are used for the temporary ports a client picks for outgoing connections.
Why do some entries say TCP/UDP?
IANA usually registers a port number for both TCP and UDP even when only one is used in practice. The Protocol column shows the transport normally used; TCP/UDP means both are in real use, such as DNS on port 53 or QUIC and HTTP/3 alongside HTTPS on 443.
Is a service guaranteed to use its listed port?
No. A port number is a convention. Any service can be run on another port, and a program listening on a port does not prove it is the listed service. Firewalls and scanners treat the list as a hint.
Which ports are listed?
Widely used assignments from the IANA registry: the classic system services, mail, directory, VPN and routing protocols, and common registered ports such as 3306 for MySQL and 5432 for PostgreSQL. It is a reference for common cases, not the full registry of tens of thousands of entries.
What is the difference between 25, 465 and 587?
Port 25 is for mail transfer between servers. Port 587 is for mail clients submitting outgoing mail, normally upgraded to TLS with STARTTLS. Port 465 is submission over TLS from the start (RFC 8314).