A port number is a logical identifier used by your operating system to distinguish between different network services running on the same machine. Ports range from 0 to 65535, and they are divided into three categories:
This command will directly show you the name of the application (e.g., node , python , docker ) and its PID. Step 2: Terminate the Conflicting Process
Certain database distributions, NoSQL instances, or local cache proxies use custom ports in the 11000–12000 range. For example, specific enterprise configurations of IBM software, database connections, or proprietary financial trading APIs bind to port numbers like 11501 to handle heavy transactional local loopback data. Dev Containers and Docker Port Mapping localhost-11501
In specialized financial networks like the Karnataka State Government's Khajane II (K2) portal, local host connections on custom ports are used to interface with local biometric devices or digital signature certificate (DSC) USB tokens. The web portal communicates with a local utility running on port 11501 to sign transactions securely. 2. Microservice and API Development
The most common error you will encounter is the "localhost refused to connect" or a similar browser error. This message is a clear sign that your browser successfully located your machine but was unable to establish a connection with a service on port 11501. A port number is a logical identifier used
Encountering a "connection refused" error when you try to access http://localhost:11501 is a common frustration. This means your browser was able to reach your computer (the localhost part) but found nothing listening on the specific port (11501). The following is a step-by-step guide to diagnose and fix this, based on common localhost troubleshooting practices.
The port falls into the registered ports range. It is not a standard default for major databases or web servers like Apache or Nginx. Therefore, seeing localhost-11501 usually indicates a custom or application-specific service running on your machine. Not directly. For HTTPS on localhost
The error usually means no software application is actively running on that specific port. You can check what is running using native terminal commands: : netstat -ano | findstr :11501 Use code with caution. macOS / Linux (Terminal) : sudo lsof -i :11501 Use code with caution.
Not directly. For HTTPS on localhost, you need to generate a self-signed certificate and configure your server for SSL/TLS, then access https://localhost:11501 . Browsers will show a security warning, which you can bypass for testing.