Port 3248: PROCOS LM — A Name in a Registry

What Port 3248 Is

Port 3248 sits in the registered ports range (1024–49151). These ports are assigned by IANA upon request from organizations that want a standardized, recognized port for their software. Unlike the well-known ports below 1024 — which carry HTTP, SSH, DNS, and other protocols that millions of systems depend on daily — registered ports are claimed by individual vendors, products, and projects of every size.

IANA's registry lists port 3248 as assigned to PROCOS LM on both TCP and UDP.¹ That assignment is the entirety of the public record.

What PROCOS LM Is

Unclear. The name suggests a license manager — "LM" is a common suffix for license management software. But PROCOS LM appears to have left no documentation, no vendor page, no forum threads, and no observed traffic analysis in any public source. It may be a product that never shipped widely, a company that dissolved, or an internal tool that someone registered and then quietly abandoned.

This is more common than it sounds. The IANA registry has thousands of entries. Some point to thriving infrastructure. Others point to software that existed briefly in the late 1990s or early 2000s and is now gone, leaving only a name in a text file.

One Other Note

Port 3248 falls within the UDP range 3224–3324, which Citrix NetScaler Gateway uses for Framehawk — its display protocol for XenDesktop and XenApp virtual desktop sessions.² This is a range assignment, not a specific port assignment. If you see UDP traffic on 3248 in a Citrix environment, Framehawk is the likely explanation. This is incidental to the IANA entry for PROCOS LM.

What to Do If You See It

If port 3248 is open or active on a system you manage, check what's listening:

On Linux or macOS:

sudo ss -tlnp | grep 3248
sudo lsof -i :3248

On Windows:

netstat -ano | findstr :3248

Match the process ID from the output against your running processes. If you don't recognize it and you're not running Citrix infrastructure, that's worth investigating.

Why Unassigned (and Forgotten) Ports Matter

The registered port range exists so that software can have a stable, predictable home — a number that firewalls can allow, that documentation can reference, that other developers can recognize. When that software disappears, the assignment remains. Port numbers are never recycled.³

This creates a useful property: if you see traffic on an obscure registered port, something real is probably listening. The question is whether that something is what you expect.