Find what runs on a port — or which port a service uses
When you see traffic on port 5432 or need to know where to point a client for redis, this tool answers both directions. Search by a port number to see the conventional service, or by a service name to find its standard port — along with the transport protocol (TCP, UDP, or both) and which IANA range the number falls in.
How it works
The page carries a curated list of common port assignments, each with its number, the transports it uses, a service name, and a description. A numeric query is matched exactly against the port number and also classified into one of the three IANA ranges: well-known (0–1023), registered (1024–49151), or dynamic/ephemeral (49152–65535). A text query is matched case-insensitively against the service name and description, so mail surfaces SMTP, IMAP, and POP3 entries together.
The three port ranges explained
IANA divides the 65,535 usable port numbers into three bands, each with a distinct purpose and access model:
Well-known ports (0–1023): assigned to foundational internet services. On Linux and most Unix-like systems, binding to a well-known port requires root privileges or CAP_NET_BIND_SERVICE. This is why production web servers often bind as root and immediately drop to a lower-privilege user, or use a reverse proxy.
Registered ports (1024–49151): assigned by IANA to specific applications on request. No root privilege is required to bind here, so application servers (PostgreSQL on 5432, Redis on 6379, MySQL on 3306) all sit in this range.
Dynamic / ephemeral ports (49152–65535): not assigned to any service. The OS assigns these automatically to the client side of outbound TCP and UDP connections. The exact range used varies by OS — Linux defaults to 32768–60999, Windows uses 49152–65535, macOS follows the IANA definition.
Commonly referenced ports at a glance
| Port | Protocol | Service |
|---|---|---|
| 22 | TCP | SSH |
| 25 | TCP | SMTP (mail transfer) |
| 53 | TCP + UDP | DNS |
| 80 | TCP | HTTP |
| 443 | TCP | HTTPS |
| 3306 | TCP | MySQL / MariaDB |
| 5432 | TCP | PostgreSQL |
| 6379 | TCP | Redis |
| 27017 | TCP | MongoDB |
| 3389 | TCP | RDP (Remote Desktop) |
Security considerations
Standard ports are conventions that clients default to, but services can run on any free port. That said, obscuring a service’s port provides minimal security — port scanning tools enumerate common services rapidly regardless. The meaningful security control is your firewall policy.
High-risk ports to consider blocking inbound at the network boundary: Telnet (23, cleartext), SMB (445, frequently targeted), RDP (3389, brute-force target), database ports (3306, 5432, 27017 — should never be internet-exposed directly). The full authoritative reference is the IANA Service Name and Transport Protocol Port Number Registry.