Port 3567: DOF Protocol Stack — The Officially Assigned Port Nobody Knows

What This Port Is

Port 3567 is assigned by IANA to the DOF Protocol Stack (DPS), the networking layer of the OpenDOF Project — an open-source Internet of Things framework that aimed to let connected devices communicate across different networks and standards.

Both TCP and UDP are registered. The assignment dates to August 2002, with a revision in April 2015.

In practice, you are unlikely to encounter DOF traffic on this port. The protocol never achieved wide adoption, and most port scanners and security databases list port 3567 as unassigned or unknown — which is the honest answer about what you'll find in the wild.

What DOF Is

DOF (Distributed Object Framework) was designed to solve a real problem: IoT devices speak dozens of incompatible protocols, and getting them to work together is painful. DOF provided a secure, object-oriented layer that could sit on top of different transports and let devices share information across network boundaries.

The OpenDOF Project published specifications and open-source SDKs for Java, C, and C#. Panasonic backed the commercial version. The most active development period was roughly 2015 to 2017.

The project appears to still exist, but the momentum did not.

What Range This Port Belongs To

Port 3567 is a registered port (the range from 1024 to 49151). Registered ports are managed by IANA, and applications can formally claim them by going through the registration process. They are neither the famous well-known ports (0-1023, which require root to bind) nor the ephemeral ports (49152-65535) that operating systems assign temporarily for outgoing connections.

A registered port assignment means someone asked IANA for this number and IANA said yes. It does not mean anyone is using it.

If You See Port 3567 Open

If you run a port scan and find 3567 open on a system, it is probably not DOF. More likely candidates:

• A developer used it arbitrarily for a local service
• A game, IoT hub, or custom application chose it for internal communication
• An old DOF-based system (rare, but possible)

How to Check What's Listening

On Linux/macOS:

# Show what process has port 3567 open
lsof -i :3567

# Or with ss
ss -tlnp sport = :3567

On Windows:

netstat -ano | findstr :3567
# Then look up the PID:
Get-Process -Id <PID>

Why Unassigned-in-Practice Ports Matter

The registered port range has 48,127 slots. IANA has formally assigned a few thousand of them. The rest are technically available — but "available" is not the same as "empty." Developers pick port numbers for countless reasons (birth years, favorite numbers, sequential incrementing from something nearby), and those informal choices layer on top of the formal registry without any coordination.

Port 3567 is the registered kind of obscure: officially spoken for, practically ignored. If you need a port for something, pick something else.