Port Reference
Search by port number or service name. App-IDs shown for policy building.
Port Reference
About this tool
About port numbers
A port number identifies a service on a host, alongside its IP address and the transport protocol (TCP or UDP). Ports run from 0 to 65535 and IANA splits them into three ranges:
- 0–1023 – well-known (system) ports, such as 22 for SSH and 443 for HTTPS
- 1024–49151 – registered ports assigned to specific applications
- 49152–65535 – dynamic or ephemeral ports that clients use for outgoing connections
Ports worth knowing
| Port | Protocol | Service |
|---|---|---|
| 22 | TCP | SSH |
| 53 | TCP/UDP | DNS |
| 80 | TCP | HTTP |
| 123 | UDP | NTP |
| 443 | TCP | HTTPS |
| 445 | TCP | SMB |
| 3389 | TCP | RDP |
FAQ
What is the difference between TCP and UDP? TCP sets up a connection and guarantees ordered delivery. UDP sends datagrams with no connection or delivery guarantee, which suits DNS queries, NTP and streaming.
What is an App-ID? On Palo Alto firewalls, App-ID identifies the application by its traffic rather than only by port, so a rule can allow one application and not just a port number.