Port 800: mdbs_daemon — The Database Service That Time Forgot

Port 800 sits in the well-known ports range with an official assignment, but chances are you'll never see anything actually using it.

What Port 800 Was For

The Internet Assigned Numbers Authority (IANA) registered port 800 for mdbs_daemon—the Message Database Server used by TeamWARE Office.¹ This was a groupware suite from the 1990s, originally developed by TeamWARE and later acquired by Fujitsu, then Sun Microsystems, and eventually Oracle.

The service handled database communications for the office suite. Clients would connect to port 800 to access shared databases. Both TCP and UDP were assigned.

Then TeamWARE Office faded into obscurity. The product disappeared. But the port assignment didn't.

The Well-Known Ports Range

Port 800 belongs to the well-known ports range (0-1023). These ports are reserved by IANA for system services and require root privileges to bind on Unix-like systems.²

Getting a well-known port assignment requires IETF Review or IESG Approval—it's not handed out lightly. Port 800 earned its spot in the 1990s when TeamWARE Office was relevant. The assignment persists even though the service doesn't.

What You'll Actually Find on Port 800

In practice? Usually nothing.

System administrators running port scans occasionally see port 800 flagged as "filtered" with the label "mdbs_daemon," but when they check with netstat or lsof, nothing is listening.³ It's a ghost—the port scanner recognizes the name from old databases, but no actual service is running.

Some network monitoring tools still log bandwidth usage labeled as "MDBS_DAEMON" when they see traffic on port 800,⁴ even though it's almost certainly something else using the port unofficially.

Why Unassigned Ports Matter

Port 800 isn't technically unassigned—it has an official designation. But it's functionally abandoned. This happens more often than you'd think in the well-known range.

Old services get port assignments, then disappear. New services need ports but can't get the abandoned ones reassigned because IANA maintains stability in the registry. So we end up with ghost towns like port 800—officially occupied, practically empty.

These orphaned assignments matter because they represent coordination that worked. The port was registered, standardized, and documented. Software across the Internet agreed that port 800 meant mdbs_daemon. That agreement held even after the software vanished.

This is infrastructure archeology. The port remains as evidence that something once existed here.

How to Check What's Actually Listening

If you want to see whether anything is actually using port 800 on your system, use one of these commands:

Using ss (recommended on modern Linux):⁵

sudo ss -tulpn | grep :800

Using netstat (traditional method):⁵

sudo netstat -tulpn | grep :800

Using lsof (shows process details):⁵

sudo lsof -i :800

You'll probably see nothing. And that's exactly what you should expect from a port assigned to software that doesn't exist anymore.