What This Port Does
Port 3622 is assigned to FF LAN Redundancy Port — the "FF" standing for FOUNDATION Fieldbus, an industrial communication protocol maintained by the FieldComm Group (formerly the Fieldbus Foundation). It operates on both TCP and UDP.
FOUNDATION Fieldbus is not a web protocol. It's not something your laptop uses. It runs in process automation environments: oil and gas refineries, chemical plants, water treatment facilities, pharmaceutical manufacturing. It's the protocol that lets sensors, actuators, and control systems talk to each other in environments where a communication failure means a very bad day.
The redundancy port specifically handles the LAN failover layer of FOUNDATION Fieldbus HSE (High Speed Ethernet) — the 100 Mbit/s Ethernet backbone that connects linking devices and host systems. When a network switch fails or a cable is cut, the redundancy system detects the break and reroutes communication. Port 3622 is part of how those devices coordinate that handoff.1
The Registered Port Range
Port 3622 sits in the registered port range (1024–49151). This range is administered by IANA, and any company or organization can apply to claim a port for their protocol. Unlike the well-known ports (0–1023), which require more scrutiny and are reserved for foundational Internet services, registered ports are essentially first-come, first-served with basic documentation.
The Fieldbus Foundation registered port 3622 in October 2002.2
The registered range has 48,128 slots. Thousands belong to industrial protocols, proprietary enterprise software, and niche applications that most Internet users will never encounter. Port 3622 is a good example: legitimately registered, actively used in heavy industry, invisible to nearly everyone else.
Will You See This Port?
Almost certainly not, unless:
- You administer a FOUNDATION Fieldbus HSE network
- You're doing security assessments on industrial control system (ICS) infrastructure
- You're a penetration tester specifically targeting operational technology (OT) environments
If you're seeing port 3622 active on a general-purpose server or workstation, it's almost certainly something else using the port informally — not FOUNDATION Fieldbus.
How to Check What's Listening
To see if anything is using port 3622 on your system:
On Linux or macOS:
On Windows:
If something appears, note the process ID and look it up. On Linux/macOS, lsof will show you the process name directly. On Windows, take the PID from netstat and check Task Manager or run tasklist | findstr <PID>.
このページは役に立ちましたか？