Port 2660: GC Monitor — A Reserved Port Nobody Uses

What Port 2660 Is

Port 2660 sits in the registered port range (1024–49151). These ports are assigned by IANA to specific services and applications — not reserved in the locked-down way of well-known ports (0–1023), but tracked and theoretically allocated to prevent collisions.

IANA's registry lists port 2660 as assigned to GC Monitor (service name: gcmonitor), over both TCP and UDP. The registrant is Gustavo Rodriguez-Rivera, a computer science professor at Purdue University whose research focused on garbage collection algorithms and memory management.¹²

GC Monitor was presumably a tool for observing garbage collector behavior in running programs — a reasonable thing to need if you're researching memory management. The port was registered. The software never achieved any known deployment.

What You'll Actually Find on Port 2660

Probably nothing.

Occasionally, Dell's OpenManage Server Administrator software has been observed using ports in this range, and security scanners sometimes flag port 2660 in that context. But there's no stable, widely-deployed service that claims this port in practice.

If you see port 2660 open on a machine, it's almost certainly something that chose the port opportunistically — a custom application, a development tool, or something that picked an obscure number hoping to avoid conflicts.

How to Check What's Using It

Linux / macOS:

# Show which process is listening on port 2660
sudo lsof -i :2660

# Or with ss:
sudo ss -tlnp | grep 2660

Windows:

netstat -aon | findstr :2660

The PID from netstat can be cross-referenced in Task Manager or with:

tasklist | findstr <PID>

Why Unassigned-in-Practice Ports Matter

The registered port range is large — over 48,000 numbers — and IANA has issued assignments for decades. Many of those registrations represent software that shipped once, or prototypes that never shipped at all. The port number persists in the registry long after the project is gone.

This matters for a few reasons:

• Security scanners flag open ports in this range. An unexpected listener on 2660 is worth investigating, even if the "official" use is benign.
• Applications sometimes collide here. If a service needs an arbitrary port, it may pick something in the registered range without checking. Two services on the same machine can conflict.
• Port 2660 is essentially free. If you're building something that needs a dedicated port for local or development use, this one is available in practice — just check the IANA registry first.¹