Port 367: MortgageWare — The Business Software That Got a Well-Known Port

Port 367 sits in the well-known ports range (0-1023), the same tier as HTTP, DNS, and SSH. But unlike those fundamental Internet protocols, port 367 was registered for a specific business application: MortgageWare, mortgage processing software from INTERLINQ Software.¹

What Is Port 367?

Port 367 is officially assigned to "mortgageware" in the IANA Service Name and Transport Protocol Port Number Registry.² It operates on both TCP and UDP protocols. The software appears to have been most active in the mid-2000s to early 2010s, used for mortgage industry data processing and integration with other mortgage systems.³

This is unusual. The well-known ports range was designed for fundamental network services that everyone needs—protocols like FTP, SMTP, and Telnet. Port 367 is different: a well-known port number reserved for a specific company's specific product.

The Port Assignment Anomaly

The Internet's port registry doesn't care about scale. Port 367 for MortgageWare sits right next to port 443 for HTTPS. One routes trillions of requests per day. The other probably handled a few thousand mortgage transactions total.

Both have the same status: officially registered well-known ports.

This happened because the early Internet was small, the port registry was managed more casually, and there was no way to predict which protocols would become universal infrastructure and which would fade into obscurity. Someone at INTERLINQ Software filled out a form, IANA assigned them port 367, and that number is now permanently reserved in the global registry.

Security Considerations

Port 367 has been flagged in various security databases as having been used by malware in the past.⁴ This doesn't mean the port itself is dangerous or that MortgageWare was malicious. It means that, like many registered ports, attackers have sometimes used it for trojan communication because it's a known number in the registry.

If you see unexpected traffic on port 367, investigate what's listening:

# Linux/macOS - Check what's using port 367
sudo lsof -i :367
sudo netstat -tulpn | grep 367

# Windows - Check what's using port 367
netstat -ano | findstr :367

Legitimate MortgageWare traffic would be rare today. Most activity on this port should be considered suspicious unless you're specifically running the software.

Why Unassigned and Obscure Ports Matter

The IANA registry contains thousands of port assignments like this one—specific software products from the 1980s, 1990s, and early 2000s that registered port numbers and then faded away. Many of these applications no longer exist. Some companies went out of business decades ago.

But the port assignments remain.

This creates a strange landscape: the port registry is full of ghosts. Reserved numbers that will never be reassigned, sitting unused forever, because the registry is designed for permanence. Once a port is assigned, it stays assigned, even if the software disappears.

Port 367 is one of these ghosts. A reminder that the Internet's infrastructure was built by humans making decisions with incomplete information, trying to organize a network whose scale they couldn't imagine.

Related Ports

• Port 365 (dtk): Another obscure registered service, for DeskTop Konnektor
• Port 366: Unassigned
• Port 368-370: Various registered services with minimal modern usage
• Port 443 (HTTPS): Just 76 numbers away, carrying most of the encrypted web