Port 1941: DIC-AIDA — A Registered Ghost

What This Port Is

Port 1941 sits in the registered port range (1024–49151). These ports are formally assigned by IANA upon request from a person or organization claiming a legitimate service. Unlike well-known ports (0–1023), registered ports don't require special OS privileges to use — any application can bind to them.

IANA's registry lists port 1941 as dic-aida, registered by Frans S.C. Witte, with a contact email at dicgroep.nl — a Dutch company. Both TCP and UDP are listed.¹

That's where the paper trail ends.

What "dic-aida" Means

Unknown. There is no RFC, no protocol specification, no product page, no open-source implementation, and no observed traffic signatures tied to this service name. The registration exists in the IANA database the same way a business license exists for a shop that never opened.

"DIC Groep" appears to be a Dutch organization, and "AIDA" is a name that could refer to anything from a marketing framework to an internal software product. Without documentation from the registrant, it's impossible to say.

This isn't unusual. Hundreds of registered ports were claimed by companies with real intentions that were never realized, or for internal proprietary software that never spread beyond the organization's walls.

What You Might Find on Port 1941

Because dic-aida has no real footprint, if you find something listening on port 1941 on one of your machines, it almost certainly isn't this service. More likely candidates:

• Custom application binding — Developers sometimes choose port numbers without checking IANA assignments
• Misconfigured software — Something that was pointed at the wrong port
• Ad hoc peer-to-peer traffic — Some applications pick ports from the registered range dynamically

How to Check What's Using It

On Linux/macOS:

# Show what process is listening on port 1941
ss -tlnp | grep 1941
# or
lsof -i :1941

On Windows:

# Show listening ports and associated processes
netstat -ano | findstr :1941
# Then look up the PID in Task Manager

If something is listening, the process name will tell you more than the port number ever could.

Why Unassigned-in-Practice Ports Matter

The registered port range has over 48,000 slots. IANA assigns them on request, but doesn't verify that protocols are ever built, documented, or deployed. The result is a registry full of names that mean nothing in practice.

This matters for two reasons. First, security tools that rely on port numbers to identify traffic will misidentify applications that choose their own ports. Second, applications that pick ports without checking IANA assignments may accidentally collide with something else — including ghost registrations like dic-aida that could theoretically be revived someday.

The honest position: port 1941 is registered but dormant. Treat any traffic on it as application-specific and investigate accordingly.