Port 3361: KV Agent — Registered, But Obscure

What Range This Port Belongs To

Port 3361 falls in the registered ports range (1024–49151). 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 temporarily by operating systems for outgoing connections).

Registered ports are assigned by IANA upon request. Any organization or developer can apply. IANA records the service name, contact information, and protocol, but it does not audit, test, or endorse the software. The registry is a directory, not a certification.¹

What IANA Says About Port 3361

IANA's registry assigns port 3361 on both TCP and UDP to KV Agent, service name kv-agent. The listed contact is Thomas Soranno at cipartners.com.¹

That's the entirety of the public record. There is no RFC, no specification, no developer documentation, no open-source implementation. The software appears to be proprietary and internally used, never broadly deployed. The registration exists; the documentation does not.

This is not unusual. The registered port space contains thousands of entries like this — products that were built, ports that were claimed, and software that either stayed internal or faded away.

Security Databases

Some port scanning databases flag port 3361 as having been associated with malicious activity in the past.² This is worth understanding correctly: it does not mean port 3361 is inherently dangerous. Malware frequently uses non-standard or obscure ports precisely because they are unlikely to be monitored. A port with no well-known service attached to it is easy to slip traffic through unnoticed.

If port 3361 appears open on a system running no software that intentionally uses it, that warrants investigation.

How to Check What's Listening on This Port

On Linux/macOS:

# Show which process is listening on port 3361
ss -tlnp | grep 3361

# Or with lsof
lsof -i :3361

On Windows:

netstat -ano | findstr :3361

The output will show the process ID (PID). Cross-reference that with Task Manager or ps aux | grep <PID> to identify the software.

With Nmap (from another machine):

nmap -sV -p 3361 <target-ip>

The -sV flag attempts service version detection. For port 3361, it will likely return unknown — because there's no public fingerprint to match against.

Why Unassigned and Obscure Ports Matter

The port numbering system depends on shared conventions. Port 443 means HTTPS everywhere, which is why your browser knows what to do when it connects to a web server. That coordination is only possible because the registry exists and people follow it.

Ports like 3361 — registered but effectively opaque — represent a different reality: the registry can capture a claim, but it cannot force documentation, adoption, or transparency. The result is port space that is technically allocated but practically unknown.

When you see an open port on a system and can't identify it from the registry, that's not a flaw in the system. That's the system being honest about its limits. The registry records intent. Only the software knows what it's actually doing.