Port 2640 carries commands to machines. Specifically, it's registered for AMI-Control, the UDP-based device control protocol from Alcorn McBride Inc.—a company that builds show control hardware for theme parks, museums, and entertainment venues. Their equipment runs attractions at Disney parks, Universal Studios, and similar venues worldwide.
It's also listed as SAI Sentlm, a license manager from Sabbagh Associates. That entry appears dormant—you're unlikely to encounter it in the wild.
What AMI-Control Does
Alcorn McBride's AMI/O hardware handles the physical inputs and outputs that run automated shows: triggering audio, moving animatronics, firing cues, reading sensors. The AMI-Control protocol is how a host controller talks to these devices over a network.
The protocol is simple by design. Commands are sent as text strings over UDP port 2640, terminated with a carriage return (0x0D). Responses come back the same way. No handshakes, no sessions—just commands and acknowledgments, fast enough to keep a show running on cue. 1
The Range This Port Belongs To
Port 2640 sits in the registered ports range (1024–49151). These ports aren't reserved for the operating system, but they are registered with IANA—meaning a vendor or standards body has formally associated them with a specific service. Registration doesn't guarantee widespread use; it just means someone filed the paperwork.
Most registered ports carry software you've never heard of: proprietary protocols, industrial control systems, specialized enterprise tools. AMI-Control is a perfect example. It's obscure to network engineers, but essential to the systems operators who maintain it.
Who Scans This Port
The SANS Internet Storm Center reports low but steady scanning activity on port 2640—generic reconnaissance bots sweeping the registered range rather than targeted attacks. Threat level is green. 2
If you're seeing unexpected traffic on 2640, it's almost certainly a scanner, not someone who knows what Alcorn McBride hardware is.
How to Check What's Listening
On Linux/macOS:
On Windows:
With nmap (from another host):
If you find something listening on 2640 and you're not running Alcorn McBride hardware, identify the process ID from the output above and trace it to the owning application.
Why Unassigned-Looking Ports Matter
The registered port range has 48,128 slots. Most are filled with things like this: real protocols built for specific hardware, used by the organizations that need them, invisible to everyone else. The port system works precisely because these assignments keep vendors from stepping on each other's toes.
Port 2640 isn't unassigned—it just isn't famous. Somewhere, a show controller is waiting on it.
Frequently Asked Questions
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