Port 2340: Unassigned — An unclaimed address in the registered range

Port 2340 has no officially assigned service. IANA lists it as unassigned in the registered port range.

What range this port belongs to

Port 2340 falls in the registered ports range (1024-49151), also called User Ports. This range sits between the well-known ports (0-1023, reserved for foundational protocols like HTTP, DNS, and SSH) and the ephemeral ports (49152-65535, used for temporary connections your OS assigns automatically).

The registered range works like this: anyone can submit a request to IANA to claim a port number for a named service. If approved, the service name gets listed in the IANA registry. Port 2340 was never claimed.

Known unofficial uses

Nothing significant. Port 2340 appears on a handful of older security reference lists as having been observed in connection with trojan activity, but this is true of many unassigned ports and says more about how malware picks port numbers (arbitrarily) than about port 2340 specifically.¹

No widely deployed application is known to use this port by convention.

How to check what's listening on this port

If you see traffic on port 2340 and want to know what's using it:

Linux / macOS:

# See what process is bound to port 2340
ss -tlnp | grep 2340
# or
lsof -i :2340

Windows:

netstat -ano | findstr :2340
# Then look up the PID:
tasklist | findstr <PID>

If something is listening on port 2340 and you didn't put it there, that's worth investigating. Unassigned ports are occasionally used by applications that needed a number, malware that needed to hide, or developers who hardcoded a port during testing and never changed it.

Why unassigned ports matter

The registered port range contains 48,128 numbers. Most of them are assigned. But thousands are still empty, and port 2340 is one of them.

That matters for a few reasons. Firewall rules often target named services. An application that uses an unassigned port doesn't benefit from the same scrutiny a well-known service would get. It flies below the radar of rules that block "known bad" ports, and it doesn't show up cleanly in traffic analysis tools that map port numbers to service names.

This is why network monitoring matters more than port-number reputation. A port number tells you where traffic is going. Only the traffic itself tells you what it is.