Port 10134 — Unassigned, But Not Unused

What Range Is This Port In?

Port 10134 falls in the registered port range (1024-49151). ¹ These are ports that exist above the well-known system ports (0-1023) but below the dynamic/ephemeral range (49152-65535). The IANA maintains a registry of assigned services in this range, but the registry is not complete—many ports remain unassigned, available for vendor-specific use or private applications.

Port 10134 specifically sits in the block 10130-10159, which shows as "Unassigned" in the official IANA registry. ¹ This means no service is officially designated to use it.

What Actually Uses It

Despite being unassigned, port 10134 is actively used by Logitech Options, the software that manages Logitech peripheral devices like the Craft Keyboard. ² The application runs a local WebSocket server on port 10134 (bound to 127.0.0.1, listening only on the local machine) to enable communication between Logitech hardware and the Options software. ²

This allows Logitech peripherals—particularly the Craft Keyboard with its customizable crown—to send input directly to the Options software, which then routes commands to open applications.

Security Note

Logitech Options listens on localhost only, which limits exposure. However, the application skips authentication steps for local WebSocket connections, which could theoretically be exploited if an attacker gains local access to the machine. ² The port is not exposed to the network, but the trade-off for convenience is reduced security.

How to Check What's Listening

If you want to see what's listening on port 10134 on your system:

On macOS:

lsof -i :10134

On Linux:

ss -tulpn | grep 10134
netstat -tulpn | grep 10134

On Windows:

netstat -ano | findstr :10134
Get-NetTCPConnection -LocalPort 10134 | Select-Object -Property State, OwningProcess

If Logitech Options is running, you'll see it listening on 127.0.0.1:10134.

Why Unassigned Ports Matter

The gap between the IANA registry and actual port usage reveals how the Internet works in practice. Large vendors like Logitech don't always formally register every port they use internally. They pick a number in the unassigned range, document it in their software, and let millions of users run that same port number. The registry becomes an official map that doesn't match the actual territory.

This isn't dangerous—most of these private ports are bound to localhost, invisible to the outside world. But it means the registry is incomplete. Port 10134 exists in a liminal space: unassigned on paper, essential in practice.