What Range This Port Belongs To
Port 1983 sits in the registered ports range, which runs from 1024 to 49151. These ports are managed by IANA — the Internet Assigned Numbers Authority — and can be registered by applications and protocols for specific uses.1
The registered range is a middle ground. Below it are the well-known ports (0–1023): the territory of HTTP, SSH, DNS, and the foundational protocols of the Internet, which require elevated system privileges to bind. Above it are the ephemeral ports (49152–65535), handed out temporarily by the OS whenever your computer needs to initiate a connection. The registered range is open territory — anyone can apply for a number, and many do, but registration doesn't guarantee adoption.
The Official Assignment: Loophole Test Protocol
IANA lists port 1983 as assigned to lhtp — the Loophole Test Protocol — on both TCP and UDP.1
This sounds more significant than it is. The Loophole Test Protocol has no widespread implementation, no notable RFC, and no presence in modern network infrastructure. It is, in the quiet bureaucratic tradition of port registries, a name attached to a number that largely goes unused. The assignment exists. The protocol does not, in any meaningful operational sense.
What Actually Uses Port 1983
Two things have been observed on port 1983 in practice:
Tales of Pirates — An MMORPG from the mid-2000s used port 1983 for game traffic. The game is now largely defunct. If you see this port in traffic logs from around 2006, someone was probably pillaging virtual ships.
Q-taz Trojan — Port 1983 has been associated with this older piece of malware. If you didn't install a pirate game and port 1983 is open and listening, that's worth investigating.2
Beyond these, general Internet scanners probe this port periodically — automated reconnaissance sweeping through registered ports looking for whatever might answer.3
How to Check What's Listening on This Port
On Linux or macOS:
On Windows:
The process ID in the output will tell you what application has claimed the port. On Linux, cross-reference it with ps aux.
Why Unassigned Ports Matter
The port system works partly because of convention and partly because of scarcity management. If every application grabbed random ports, diagnosing network problems would be impossible. The registered range exists so that software has a stable, predictable home.
Ports like 1983 — registered to something that never shipped — are placeholders. They hold territory. They prevent collision. And they serve as a reminder that the port registry is a living document: full of ambition, legacy assignments, and the occasional ghost.
Frequently Asked Questions
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