localhost is a hostname that refers to the local machine or the computer you're currently using. It's equivalent to 127.0.0.1 , which is a special IP address known as a loopback address. This address allows a computer to communicate with itself, essentially allowing services running on the same machine to interact with each other.
localhost-11501 is not a magic number—it is simply a on your local machine, often used for custom development servers, Docker containers, or specialized applications. Understanding how to inspect, troubleshoot, and secure ports like 11501 is a fundamental skill for any developer working with networked software.
: Your security software might block Port 11501. Temporarily disable your firewall to see if the connection works, or add an exception for this port.
: Local testing environments for physical equipment that stream telemetry data locally.
If your terminal shows that an old or frozen instance of your program is occupying the port, your new script won't be able to bind to it. To clear port 11501 manually:
While port numbers can technically be assigned arbitrarily by any software developer, port 11501 is historically and practically observed in a few distinct technical landscapes: 1. Industrial Hardware Integration (Moxa UPort) UPort 1150I - USB-to-Serial Converters - Moxa
While localhost:11501 is a development tool, it also presents unique security challenges that must be managed.