Port 3678: ipr-dglt — A Ghost in the Registry

What Port 3678 Is

Port 3678 sits in the registered port range (1024-49151). These ports are not reserved for the operating system, and they're not freely ephemeral either. They occupy the middle space: anyone with a legitimate reason can register one with IANA, claim the name, and own that port number in the official record.

Port 3678 was registered in January 2003 under the service name ipr-dglt, described as "DataGuardianLT." The registrant was Bruce Carlson. The registration covers both TCP and UDP.¹

That's everything the official record says.

What DataGuardianLT Was

No one seems to know.

The software left no documentation, no support forums, no product pages, and no mentions in the technical literature. Whatever DataGuardianLT was — some kind of intellectual property or data protection tool, based on the name — it didn't survive long enough to leave a trace.

This isn't unusual. The registered port range is full of these ghost registrations: software that shipped to a handful of customers, internal tools that got registered "just in case," products that were announced and then quietly canceled. The registration process in the early 2000s required little more than a name and a contact.²

The port is still officially assigned. The service is gone.

What That Means for You

If you see traffic on port 3678, it isn't DataGuardianLT. It's something else — a custom application, a misconfigured service, or occasionally malware picking an obscure port precisely because it looks uninteresting.

To check what's actually listening on port 3678:

On Linux or macOS:

# Show what process is using port 3678
ss -tlnp sport = :3678
# Or with lsof:
lsof -i :3678

On Windows:

# Show listening ports and the processes behind them
netstat -ano | findstr :3678
# Then look up the PID:
tasklist | findstr <PID>

If something shows up, the process name will tell you more than the port number ever will.

Why Ghost Ports Exist

The registered port range has over 48,000 slots. IANA has assigned a fraction of them, but even among the assigned ones, many are like port 3678: technically claimed, practically abandoned.

This matters for a few reasons:

• Port scanners treat assigned ports differently. A port with a known registration gets categorized as "ipr-dglt traffic" in some tools, which can mask what's actually there.
• Firewall rules sometimes reference port names. Rules written against a service name inherit whatever assumptions come with it.
• Obscurity isn't security. Running a service on an obscure port buys a little noise reduction, not protection.

The registered port space is a historical record as much as a technical one. Port 3678 is a small fossil from 2003 — evidence of a product that briefly existed, got its official paperwork in order, and then disappeared.