Port 1959: SIMP Channel — A Registered Ghost

What Port 1959 Is

Port 1959 sits in the registered ports range (1024–49151). These ports are allocated by IANA for specific services — not reserved like the well-known ports below 1024, but not wild like the ephemeral ports above 49151 either. When a developer or organization wants a consistent, recognized home for their protocol, they apply to IANA and get a number.

Port 1959 was registered. IANA's official record lists it as:¹

• Service name: simp-all
• Protocol: TCP and UDP
• Description: SIMP Channel
• Contact: Tim Hunnewell, thunnewell@pinna.com

That's everything. The registry contains no RFC reference, no specification document, no pointer to further reading.

The Protocol That Wasn't

"SIMP Channel" appears in IANA's database and essentially nowhere else. There is no RFC defining it, no open-source implementation, no network scanner signatures, no forum threads asking why port 1959 is open. The contact domain — pinna.com — has no surviving presence.

This is not unusual. In the 1990s, IANA's registration process was looser. Organizations registered ports for protocols they planned to build, or built but never deployed widely, or deployed internally without the world ever noticing. The registration remains in the registry indefinitely; the software doesn't have to.²

Port 1959 is a tombstone. Someone had a protocol called SIMP Channel. It was registered. It is gone.

What It Means If You See This Port Open

If port 1959 is listening on a machine you're responsible for, it is not "SIMP Channel" — that protocol is effectively extinct. It is something else: a custom application, a game server, development tooling, or something you should investigate.

On Linux/macOS:

sudo ss -tlnp | grep 1959
# or
sudo lsof -i :1959

On Windows:

netstat -ano | findstr :1959
# Then look up the PID:
tasklist | findstr <PID>

If you find something listening there and you don't recognize it, find out what it is before deciding it's fine.

Why Unassigned (and Forgotten) Ports Matter

The registered ports range contains thousands of entries like port 1959 — officially claimed, practically abandoned. This creates a real ambiguity: seeing a registered port number gives a false sense of legitimacy. "Oh, that's SIMP Channel" sounds official. It isn't.

The honest reality is that roughly 49,000 ports exist in the registered range. A fraction are used by protocols everyone knows (HTTP on 8080, PostgreSQL on 5432, MySQL on 3306). The rest are a mix of active niche services, corporate protocols nobody outside one company uses, and registrations like this one — names attached to protocols that never shipped or quietly disappeared.

The port number tells you where to knock. It does not tell you who answers.