Port 2696 — Unassigned Registered Port

What Range This Port Belongs To

Port 2696 is a registered port (also called a user port), in the range 1024–49151. IANA maintains this range as a registry where software vendors and protocol designers can formally claim a port number for their service. Port 2696 has no such claim — IANA lists it as unassigned.¹

This is not unusual. The registered range contains tens of thousands of ports, and many sit unclaimed. Unassigned ports aren't broken or forbidden. They're simply available — a gap in the registry that nobody has filled.

Observed Unofficial Uses

Port scanning databases and security tools have informally associated port 2696 with Cisco Nexus 1000V Virtual Supervisor Module (VSM) traffic.² The Nexus 1000V was a distributed virtual switch for VMware vSphere environments — it let network teams apply physical switch policies to virtual machine traffic. The VSM was its control plane, running as a virtual machine itself.

This association was never formally registered with IANA. Cisco's own documentation for the Nexus 1000V lists various management and control-plane ports, and port 2696 appears in third-party port databases as a reported observation rather than an official designation.

Worth noting: Cisco announced end-of-sale for the Nexus 1000V in 2016 and end-of-support in 2018.³ If you see traffic on port 2696 today, it's not likely coming from that product.

How to Check What Is Listening on This Port

If port 2696 shows up in your environment, find out what's using it:

On Linux or macOS:

# Show the process listening on port 2696
sudo ss -tlnp | grep 2696

# Or with lsof
sudo lsof -i :2696

On Windows:

netstat -ano | findstr :2696

Then take the process ID from the output and look it up:

# Linux/macOS
ps aux | grep <PID>

# Windows (in Task Manager, or)
tasklist | findstr <PID>

Why Unassigned Ports Matter

The port registry exists so that software can reliably find other software. When a service registers a port, anything that needs to reach it knows where to knock. Unassigned ports are the gaps — the addresses that haven't been spoken for.

They matter for a few reasons:

• Security scanning: Unexpected listeners on unassigned ports are worth investigating. There's no legitimate "official" service that should be there, which makes any activity more conspicuous.
• Local conventions: Teams sometimes use unassigned ports for internal services, choosing numbers unlikely to conflict with anything else.
• Malware: Historically, some malicious software has used unassigned registered ports precisely because firewall rules tend to be more permissive here than in the well-known range (0–1023).

An unassigned port with an active listener isn't automatically a problem. But it's a question that deserves an answer.