Port 181: Unify — The Ghost Assignment

Port 181 sits in the well-known ports range with an official assignment, but if you search for what actually uses it, you will find almost nothing. This is a ghost assignment: a name in the registry, a date of registration, and then silence.

What Port 181 Is Assigned To

According to the IANA registry, port 181 is assigned to a service called "Unify" for both TCP and UDP. The assignment was registered to Daegis Inc., with a modification date of July 31, 2012.¹

That is about all the official documentation says.

Who Is Daegis Inc.?

Daegis Inc. was a software company that specialized in eDiscovery, archiving, and data management solutions.² The company started as Unify Corporation in 1980, developing database management systems and 4GL development tools for Unix and later Windows.³

In 2010, Unify Corporation acquired Daegis, an eDiscovery solutions provider, for approximately $38 million.⁴ In 2011, the merged company changed its name to Daegis. In 2015, OpenText acquired Daegis.⁵

The company made software for legal discovery, archiving, and information governance. Not telecommunications. Not real-time protocols. Enterprise software for searching through old emails and documents during lawsuits.

What the "Unify" Service Actually Does

Nobody seems to know.

There is no RFC. No protocol specification. No documentation explaining what the Unify service on port 181 is supposed to do. Network security databases list the port but provide no meaningful detail about its purpose.⁶

Some sources incorrectly suggest port 181 is associated with SNMP, but that is wrong—SNMP uses ports 161 and 162.⁷ Other sources simply state that port 181 "is not a reserved port number for any specific service," which contradicts the IANA registry entirely.

The most honest answer: port 181 was assigned to Daegis Inc. in 2012, probably for some internal service or future product feature. Whatever it was, it either never launched, never gained adoption, or was used so narrowly that no public documentation exists.

Why This Happens

The well-known ports range (0-1023) was designed when the Internet was smaller and assignments were more informal. Companies could request a port for a planned service, receive the assignment, and then... the product changes. The company pivots. The service never ships. The port remains registered.

IANA does not aggressively reclaim unused assignments. Once a port is assigned, it tends to stay assigned unless someone explicitly requests de-assignment. Port 181 sits in the registry like an unclaimed reservation at a restaurant: the table is technically taken, but nobody ever shows up.

What This Means for You

If you see port 181 open on your network, it is almost certainly not the official "Unify" service. It could be:

• A proprietary application using an available port number
• Malware or a backdoor (historically, some trojans have used this port)⁸
• A misconfigured service that picked an arbitrary port
• Nothing at all—just a firewall rule that was never cleaned up

To check what is actually listening on port 181:

# On Linux/Mac
sudo lsof -i :181
sudo netstat -tulpn | grep :181

# On Windows
netstat -ano | findstr :181

If something is listening and you do not recognize it, investigate. Just because a port has an official assignment does not mean that assignment is what you will find in the wild.

The Larger Pattern

Port 181 is part of a larger pattern in the well-known ports range: assignments that made sense at the time, for companies and products that have since changed, merged, or disappeared. The Internet's port registry is not just a technical document—it is an archaeological record of software that was planned, launched, or abandoned.

Somewhere in a backup tape or a forgotten codebase, there might be a Daegis product that actually used port 181. Or maybe the assignment was precautionary, reserved for a feature that never shipped. Either way, the port remains: a name without a protocol, an assignment without evidence.

This is the Internet's version of a ghost town. The street sign is still there. The lot was claimed. But nobody ever built the house.

Related Ports

• Port 161/162: SNMP (Simple Network Management Protocol)—often confused with 181
• Port 80: HTTP—the actual well-known port everyone uses
• Port 443: HTTPS—the encrypted version everyone uses