How to close TCP and UDP ports via windows command line

Question

Does somebody knows how to close a TCP or UDP socket for a single connection via windows command line?

Googling about this, I saw some people asking the same thing. But the answers looked like a manual page of netstat or netsh commands focusing on how to monitor the ports. I don't want answers on how to monitor them (I already do this). I want to close/kill them.

EDIT, for clarification: Let's say that my server listens TCP port 80. A client makes a connection and port 56789 is allocated for it. Then, I discover that this connection is undesired (e.g. this user is doing bad things, we asked them to stop but the connection didn't get dropped somewhere along the way). Normally, I would add a firewall to do the job, but this would take some time, and I was in an emergency situation. Killing the process that owns the connection is really a bad idea here because this would take down the server (all users would lose functionality when we just want to selectively and temporally drop this one connection).

Answer 1

1. open cmd

   • type in netstat -a -n -o

   • find TCP [the IP address]:[port number] .... #[target_PID]# (ditto for UDP)

   • (Btw, kill [target_PID] didn't work for me)

2. CTRL+ALT+DELETE and choose "start task manager"

   • Click on "Processes" tab

   • Enable "PID" column by going to: View > Select Columns > Check the box for PID

   • Find the PID of interest and "END PROCESS"

3. Now you can rerun the server on [the IP address]:[port number] without a problem