Port 3267: IBM Dial Out — A registered ghost

What Port 3267 Is

Port 3267 is registered with IANA for a service called IBM Dial Out (ibm-dial-out), assigned on both TCP and UDP. The registrant is Skip Booth at IBM.

That's where the story gets thin. IBM Dial Out was part of IBM's older enterprise networking stack, likely designed for dial-up connections from IBM systems — the kind of infrastructure that existed before always-on broadband made dial-out connections obsolete. No RFC defines the protocol. No modern documentation describes how it worked. The IANA entry is, effectively, a headstone.

What Range This Port Belongs To

Port 3267 falls in the registered ports range (1024–49151). IANA maintains this range for services that have formally requested assignments, but "registered" doesn't mean "active." It means someone once filed the paperwork.

Registered ports differ from well-known ports (0–1023) in one important way: well-known ports are guarded and require significant justification to claim. Registered ports are more loosely controlled. The result is a range filled with a mix of actively used services, legacy assignments no one uses anymore, and gaps where nothing was ever claimed.

Port 3267 is a legacy assignment. The service it describes is almost certainly not running on any network you'll encounter in 2026.

What's Actually Listening on Port 3267

If you see something on port 3267, it's not IBM Dial Out. It's either:

• An application that picked this port arbitrarily — developers sometimes choose registered-but-dormant ports precisely because nothing is using them
• A game, custom service, or internal tool with no public documentation
• Ephemeral traffic — operating systems assign outgoing connections to temporary ports from a range that can include 3267

To check what's actually using port 3267 on your machine:

# macOS / Linux
sudo lsof -i :3267

# Or with netstat
netstat -anp | grep 3267

# Windows
netstat -ano | findstr :3267
# Then look up the PID in Task Manager

Why Dormant Assignments Matter

The port number registry is finite — 65,535 ports total. When a registered port goes dormant, it creates ambiguity. Another service can't officially claim port 3267 without IANA intervention, even though IBM Dial Out hasn't been relevant for decades.

This is the quiet friction of legacy infrastructure. The Internet runs on protocols and assignments made in the 1980s and 1990s, some of which are alive and thriving (port 22 for SSH, port 443 for HTTPS), and some of which are just names in a registry, preserved because nobody ever bothered to clean them up.

Port 3267 is the latter. It's registered, technically claimed, and almost certainly running nothing anywhere.