Port 3162: SFLM — The License Server Port Nobody Talks About

What Port 3162 Is

Port 3162 is officially registered with IANA for SFLM — the Standard Floating License Manager, a network license management system developed by Silvaco, an electronic design automation (EDA) company.¹

This isn't a mystery port. It has a real assignment. It's just that Silvaco's tools serve a narrow audience: chip designers and semiconductor engineers. If you've never worked in that world, you've likely never heard of SFLM — or noticed this port.

What SFLM Does

Silvaco makes software for simulating and designing semiconductor devices and circuits. That software is expensive. Rather than sell individual licenses to every engineer at a company, Silvaco offers floating licenses — a pool of licenses that the team shares.

SFLM is the license server that manages that pool. When an engineer opens a Silvaco tool, it checks out a license from the SFLM server over port 3162. When they're done, the license goes back into the pool for someone else to use.²

Port 111 (the RPC portmapper) is also involved in older SFLM versions. Port 3162 is the primary channel in current deployments.

What Range This Port Belongs To

Port 3162 sits in the registered port range (1024–49151). These ports are not controlled by the operating system the way well-known ports (0–1023) are — any user-level process can open them. But IANA maintains a registry of which services have formally claimed which numbers.

Registered ports are a gentleman's agreement. IANA records the assignment; nothing technically prevents another application from using the same port number. In practice, conflicts are rare but not impossible — especially for ports registered by niche software that most sysadmins have never deployed.

If You See Port 3162 Open

On a machine you own or manage, port 3162 being open almost certainly means someone has installed and started an SFLM license server. This is expected behavior in an EDA engineering environment.

On a machine you don't recognize, it's worth investigating. Any open port that isn't explained is worth a second look.

To check what's listening:

# Linux / macOS
sudo ss -tlnp | grep 3162
sudo lsof -i :3162

# Windows
netstat -ano | findstr :3162

The output will show which process has the port open. On a legitimate SFLM deployment, you'll see the Silvaco license daemon.

Why Ports Like This Exist

The IANA registry has thousands of entries like port 3162 — formally assigned, rarely discussed, used by specific industries and forgotten by everyone else. This is the ecosystem working as intended.

The alternative is chaos: applications picking ports at random, colliding with each other, impossible to audit. The registry gives every service a home. Whether anyone visits that home is a different question.