Port 2621: Miles Apart Jukebox Server — Officially Reserved, Practically Forgotten

What This Port Is

Port 2621 sits in the registered ports range (1024-49151) and carries an official IANA assignment: the Miles Apart Jukebox Server, registered by Michael Rathmann under the protocol name miles-apart, supporting both TCP and UDP.¹

In practice, the Miles Apart Jukebox Server has left almost no footprint on the public Internet. No documentation, no source code, no user community. The assignment exists in the registry. The software, for all practical purposes, does not.

The Registered Ports Range

Ports 1024 through 49151 are called registered ports. Unlike the well-known ports (0-1023), you don't need elevated privileges to bind to them. Anyone can request an IANA registration for a port in this range by submitting an application — and IANA will record it.

The registry has thousands of entries like port 2621: assigned to applications that were submitted, approved, and then quietly abandoned. The port number is reserved on paper. Nothing enforces the reservation in practice. If you want to run your own service on port 2621 on your own systems, nothing stops you.²

What You'll Actually Find Here

If a port scanner shows activity on 2621, it isn't the jukebox server. More likely candidates:

• Developer services running on ad-hoc ports during testing
• Game servers or peer-to-peer applications using it as an ephemeral or configured port
• Malware — any unused registered port can be repurposed by software that wants to avoid well-known port blocklists

The port has appeared in some security scanner databases as historically associated with malicious software, though no specific malware family is definitively linked to it.³

How to Check What's Using It

# Linux / macOS — show what process is bound to port 2621
sudo ss -tlnp sport = :2621
sudo lsof -i :2621

# Windows — show process using port 2621
netstat -ano | findstr :2621

If the output is empty, nothing is listening. If something appears, the process name and PID will tell you what it actually is.

Why Gaps Like This Exist

The registered port space has over 48,000 slots. IANA has assigned a fraction of them. Most of those assignments are for software that still exists and is actively used. But a meaningful number — port 2621 among them — are reserved for projects that never gained traction, companies that no longer exist, or developers who submitted an application once and moved on.

The Internet does not clean up after itself. A port number registered in 1998 for a jukebox application will still show that assignment in 2026, even if the last machine running that software was decommissioned a decade ago.

That's not a flaw in the system. It's an artifact of how the Internet grows: by accretion, not revision.