What Range This Port Belongs To
Port 2403 sits in the registered ports range, which spans 1024 through 49151. These ports aren't claimed by the core Internet protocols — HTTP, FTP, SSH, SMTP — but they're not random either. Any software vendor can apply to IANA to reserve a port number for their application. IANA maintains the registry, prevents collisions, and keeps a public record.
Registered doesn't mean in active use. It means someone filed the paperwork.
What IANA Says
IANA officially assigns port 2403 (both TCP and UDP) to TaskMaster 2000 Web, registered by Ed Odjaghian at Datacap Systems. Datacap was a document capture and workflow automation company — TaskMaster 2000 was one of their products, likely from around the turn of the millennium. The product has long since been superseded or discontinued, but the port assignment remains in the registry.1
The FileMaker Confusion
Search port 2403 on most port reference sites and you'll see it listed as a FileMaker Database Server port. This is inaccurate. FileMaker (now Claris) uses ports like 5003, 80, 443, and 2399 — not 2403.2 The misattribution appears to have spread from one poorly sourced database to the next, where it now exists as a confident-sounding error across dozens of sites.
This happens more than you'd expect in the port ecosystem. Nobody audits the reference databases. Copy-paste compounds over years.
Is Anything Actually Using This Port?
Almost certainly not TaskMaster 2000 Web. If you see port 2403 active on a system, it's more likely:
- A custom internal application that picked an obscure registered port
- Dynamic port assignment that happened to land here temporarily
- Something worth investigating
How to Check What's Listening
On any system, you can see what process (if any) has bound to port 2403:
Linux / macOS:
Windows:
The process ID in the output can be cross-referenced in Task Manager or with tasklist to identify the application.
Why Unassigned-in-Practice Ports Matter
The registered port range contains thousands of ports like this one — assigned to applications nobody uses anymore, or applications so niche they never appeared on more than a handful of servers. They matter for a few reasons:
Firewall rules. A port being "registered" carries no security guarantee. If something is listening on 2403 on your network and you didn't put it there, find out what it is.
Port selection for new software. Developers picking ports for internal tools sometimes search the registered range for something "free." A port like this — assigned but dormant — might look available. It's technically taken.
Inventory. Security teams doing port scanning need to distinguish between expected services and surprises. Understanding that 2403 has an obscure registration (not FileMaker, not a standard protocol) helps contextualize scan results correctly.
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