How to free a port locked by a killed process?

Question

I have problem same as in this question.

PID exists in netstat but does not exist in task manager

I have discovered a running process with PID 26376 listening on port 9001 and 9002 as when I try to run my program(as a service) which binds to that port it fails.

But when I try to kill it using taskkill /PID it says that the process 26376 is not found. Similarly when I try to find the process in task manager with "Show processes from all users" selected, I couldn't find it anywhere.

And the accepted answer says:

What may be happening is that your process had a TCP port open when it crashed or otherwise exited without explicitly closing it. Normally the OS cleans up these sorts of things, but only when the process record goes away.

I am working on a C++ code and to fix an unknown/unresolved issue I am doing taskkill which sometimes locks the port. How do I free it on next use without restarting the whole OS? Is there any way to free such ports?

@DavidSchwartz Nope. Port stays in use by previous PID until I restart windows. — SMUsamaShah, Jan 05 '17 at 16:21
Questions like these need to name the installed anti-malware product. — Hans Passant, Jan 05 '17 at 16:36
No anti malware is installed. The question I quoted is how the port gets locked. — SMUsamaShah, Jan 05 '17 at 17:13
Might be caused by a faulty device driver (not necessarily a network driver) so it may be worth checking whether your OEM has released updated versions. Could also be that a child process is still alive and has inherited a handle to the socket, or that the parent process kept a handle to the killed process. — Harry Johnston, Jan 05 '17 at 23:19

score -1 · Answer 1 · edited May 23 '17 at 12:26

-1

The TCP TIME-WAIT state will remain for 2MSL , so that the port will still be held open. You can set socketopt SO_REUSEADDR, it will work.

See this.

edited May 23 '17 at 12:26

Community

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answered Apr 25 '17 at 07:28

Miffa Young

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This is about LISTENING ports, not TIME_WAIT ports. – user207421 Apr 26 '17 at 05:32
If you stop your server process， the listening port will be time_wait. – Miffa Young Jul 09 '20 at 02:35

How to free a port locked by a killed process?

1 Answers1