Port 2365: Unassigned — Unclaimed Territory in the Registered Range

Port 2365 belongs to the registered port range (1024–49151). IANA has not assigned it to any official service.

What the Registered Range Means

Port numbers are divided into three ranges:

• Well-known ports (0–1023): Reserved for core Internet services. HTTP lives at 80. SSH at 22. These are assigned by IANA and require elevated privileges to open on most systems.
• Registered ports (1024–49151): Available for applications to register with IANA. Anyone can submit a request. Many are officially assigned (PostgreSQL at 5432, Redis at 6379). Many are not.
• Dynamic/ephemeral ports (49152–65535): Used temporarily by your operating system when it needs an outbound connection. They're assigned and released constantly, thousands of times a day.

Port 2365 sits in the middle range — the registered range — but no one has claimed it. There's no RFC, no official service name, no protocol specification. It's a number without a story.

Known Unofficial Uses

Port 2365 has no widely documented unofficial uses in legitimate software. It has appeared in security databases as historically associated with malicious traffic — flagged by tools like AuditMyPC and Trend Micro's trojan port lists as a port that has been used by malware in the past.¹²

This doesn't mean traffic on port 2365 is malicious. Malware authors frequently pick unassigned ports precisely because they're quiet — no legitimate service is generating background noise, so communication blends into the silence. But security tools flag the history, not a guaranteed present threat.

If You See Traffic on This Port

Check what's listening:

On Linux/macOS:

# Show what process is using port 2365
sudo ss -tlnp | grep 2365
# or
sudo lsof -i :2365

On Windows:

netstat -ano | findstr :2365

The process ID in the output can be matched to a running application in Task Manager or via tasklist.

If something is listening on port 2365 and you don't recognize it, investigate. Unassigned ports are occasionally chosen by legitimate applications (custom software, games, internal tools) that never bothered registering with IANA. They're also occasionally chosen by things you don't want running.

Why Unassigned Ports Exist

IANA maintains the port registry, but registration is voluntary. Developers can choose any unassigned port for their application without registering — and most don't bother. The result is a registry with thousands of gaps: numbers that exist, but belong to no one officially.

These gaps serve the ecosystem. Ephemeral ports need room to breathe. Custom internal services need ports that won't collide with standard software. The blank space is intentional.

Port 2365 is one of those gaps. Neither dangerous nor useful by definition — just unclaimed.