Port 3355: Unassigned — A Quiet Port with a Quiet History

What Range This Port Belongs To

Port 3355 sits in the registered port range (1024–49151). These ports are tracked by IANA, but "tracked" doesn't mean occupied. IANA maintains a registry of service-to-port assignments, and 3355 currently has no active entry. ¹

The registered range exists as a middle ground: well-known ports (0–1023) are tightly controlled and require IANA approval. Dynamic or ephemeral ports (49152–65535) are freely available for temporary connections. Registered ports are the space in between — assigned by request, released when abandoned, and occasionally claimed informally by applications that never bothered to register.

Port 3355 is unclaimed in that space.

What Has Used This Port

Ordinox Dbase

Older port databases list port 3355 as "Ordinox Dbase," an obscure database application. There is no active RFC, no vendor documentation, and no modern software that claims this assignment. Whatever Ordinox was, it's gone. The name persists only as a ghost in legacy port lists.

Backdoor.Hogle

The most documented association with port 3355 is a trojan: Backdoor.Hogle, catalogued by Symantec in the early 2000s. The trojan opened port 3355 on infected Windows machines and turned them into anonymous SMTP proxy servers — spam relays operating without the owner's knowledge. ²

This is not a security concern for modern systems running current software. It's historical context: unassigned ports attract opportunistic use, and Backdoor.Hogle found 3355 convenient precisely because nothing official was expected there.

Application-Specific Uses

Like most unassigned registered ports, 3355 sees occasional use by custom applications, development servers, and internal tooling that needed a port and picked one arbitrarily. There's no pattern and no dominant use case.

How to Check What's Listening

If you see traffic on port 3355 and want to know why:

On Linux/macOS:

# Show what process is listening on port 3355
ss -tlnp | grep 3355
# or
lsof -i :3355

On Windows:

netstat -ano | findstr :3355

The process ID from netstat can be matched to an application name in Task Manager.

Why Unassigned Ports Matter

The port numbering system only works because most of it is empty. 65,535 ports exist; a small fraction have defined purposes. The rest are available for applications to use, operating systems to assign temporarily, and — occasionally — for things that shouldn't be there.

An unassigned port isn't a problem. An unexpected open port is worth understanding. The distinction matters: port 3355 being open on a server you control, running a service you recognize, is completely normal. Port 3355 being open when you don't know why is worth a look.