Port 3486: IFSF Heartbeat — The Pulse of the Forecourt

Every device at a gas station forecourt has a job to do. The fuel dispenser measures and pumps. The outdoor payment terminal handles your card. The tank level gauge watches the underground reservoir. The price sign shows what it'll cost.

They all need to talk to each other. And before any of them can trust the others, they need to know who's actually there.

That's port 3486.

What Runs on This Port

Port 3486 is the official IANA-registered heartbeat port for the IFSF protocol — the International Forecourt Standards Forum's standard for connecting equipment at fuel stations.¹

Every IFSF-compliant device broadcasts a heartbeat message on this port at regular intervals. The message is simple: here's who I am, here's my status. When a device stops broadcasting, the others notice. The silent device gets removed from the active table. It's treated as gone until it comes back.

IFSF heartbeats travel over UDP — connectionless, low overhead, fire-and-forget. That's the right choice for a broadcast meant to reach everyone on the local network simultaneously.²

The International Forecourt Standards Forum

IFSF is a global consortium that writes the technical standards connecting forecourt equipment — the dispensers, tank gauges, car washes, price signs, and payment terminals that make a modern fuel station work.³ Without a common protocol, every piece of equipment would need custom integration with every other piece. With it, a dispenser from one manufacturer can talk to a payment system from another.

The standard was designed for the physically harsh, operationally critical environment of a fuel station: outdoor temperature swings, electromagnetic noise from pumps and motors, and the requirement that if something fails, the operator needs to know immediately.

The heartbeat solves the detection problem. You can't wait for a transaction to fail to discover that a dispenser is offline. The heartbeat tells you now.

What the Heartbeat Contains

Each IFSF heartbeat carries a Logical Node Address (LNA) — a unique identifier for the device on the network — along with a device status byte. When the network controller receives it, it resets that device's timer. When the timer expires without a new heartbeat, the device is marked offline.⁴

The interval is typically a few seconds. Miss a few, and you're considered gone.

Port Range

Port 3486 sits in the registered port range (1024–49151). These ports are assigned by IANA for specific services — not reserved as strictly as the well-known ports below 1024, but formally recorded to prevent conflicts. IFSF registered this port in May 2002.¹

You won't encounter port 3486 on a typical server or desktop. This is forecourt infrastructure — it lives at gas stations, fuel depots, and fleet fueling sites.

Checking What's Listening

To see if anything is using port 3486 on your system:

macOS / Linux:

# Check for listeners
sudo lsof -i :3486

# Or with ss (Linux)
ss -tulpn | grep 3486

Windows:

netstat -ano | findstr :3486

If something shows up, it's either IFSF software or — more likely — a local application that chose this port informally. Cross-reference the process ID against your running services to identify it.

Why Unassigned Ports Matter

Most of the registered range sits empty. IANA has assigned only a fraction of the 48,128 ports between 1024 and 49151. The rest exist as a commons — available for private use, local services, and applications that never bothered to register.

This matters because collisions happen. Two applications picking the same unregistered port on the same machine is a real failure mode. The heartbeat that was supposed to reach the fuel dispenser ends up at a database instead. Registration is how the protocol ecosystem avoids this — a public record of what's supposed to live where.

Port 3486 is one of thousands of registered ports that most people will never encounter. It runs in the background of infrastructure you depend on, doing its quiet work: broadcasting existence, confirming presence, keeping the network honest about who's alive.