The terminal window on Eliza’s laptop had been blinking for three hours. Not with code, not with errors—just a steady, rhythmic pulse of a single line:

Ensure that your software is configured to listen only on localhost (127.0.0.1) and not on "0.0.0.0" (which makes the port accessible to anyone on your local Wi-Fi network). Conclusion

If you have ever glanced at your terminal, debug console, or browser address bar and noticed the obscure address , you might have done a double-take. Unlike the ubiquitous localhost:3000 (React) or localhost:5000 (Flask), port 11501 is not a standard default for major frameworks. So what is it?

tasklist | findstr <PID>