While running my Kestrel application from Visual Studio 2017 (Windows 10), I'm getting this line in my command prompt:

"Unable to bind to http://localhost:50067 on the IPv4 loopback interface: 'An attempt was made to access a socket in a way forbidden by its access permissions'."

And after that it is mentioning that

      Unable to start Kestrel.

For your reference, please look at the screenshot as well

Unable to bind to port number

What is the reason behind it?

What I did is, check the port from the command netstat -a.

Note - netstat -a in the “Command Prompt” window, and press “Enter.” The computer displays a list of all open TCP and UDP ports

I’m unable to find my port number in that lists as well.

  • Try this article also it maybe helpful to see netstat output. appuals.com/… – Ed B Sep 26 at 2:54
  • I've tried the ways mentioned in it but that don't help me to resolve the issue – user2422044 Sep 26 at 5:10
  • Somewhere is mentioned check netstat -o to see where this socket is being held, and I found out that there are lots of port it is showing. But the above port number is not showing. – user2422044 Sep 26 at 5:40

After Windows 10 Update KB4074588, some ports are reserved by Windows and applications cannot bind to these ports. 50067 is in the blocked range.

You can use netsh interface ipv4 show excludedportrange protocol=tcp to list the reserved ranges.

excludedportrange list

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.