Freeing up a TCP/IP port?

Question

netstat -tulnap shows me what ports are in use. How to free up a port in Linux?

Answer 1

To a kill a specific port in Linux use below command

sudo fuser -k Port_Number/tcp

replace Port_Number with your occupied port.

Answer 2

I think the only way will be to stop the process which has opened the port.

Answer 3

You can use tcpkill (part of the dsniff package) to kill the connection that's on the port you need:

sudo tcpkill -9 port PORT_NUMBER

Answer 4

In terminal type :

netstat -anp|grep "port_number"

It will show the port details. Go to last column. It will be in this format . For example :- PID/java

then execute :

kill -9 PID. Worked on Centos5

Answer 5

Kill the process that is listening to the port in question. I believe netstat shows you process ids.

Answer 6

If you really want to kill a process immediately, you send it a KILL signal instead of a TERM signal (the latter a request to stop, the first will take effect immediately without any cleanup). It is easy to do:

kill -KILL <pid>

Be aware however that depending on the program you are stopping, its state may get badly corrupted when doing so. You normally only want to send a KILL signal when normal termination does not work. I'm wondering what the underlying problem is that you try to solve and whether killing is the right solution.