Freeing up a TCP/IP port?

Question

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

score 277 · Answer 1 · edited Dec 08 '21 at 23:52

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As the others have said, you'll have to kill all processes that are listening on that port. The easiest way to do that would be to use the fuser(1) command. For example, to see all of the processes listening for HTTP requests on port 80 (run as root or use sudo):

# fuser 80/tcp

If you want to kill them, then just add the -k option.

edited Dec 08 '21 at 23:52

hmatar

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answered Apr 15 '09 at 07:55

uzi

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I found that sending a request to the port also cleans it (i am no linux expert though) – Matej Jan 18 '14 at 16:31
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To install fuser on Debian: sudo apt-get install psmisc (http://bitflop.com/document/107) – Korneel Mar 18 '14 at 16:30
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It worked, but I had to install psmisc too on CentOs 7 (`sudo yum install psmisc`) – Marlon Bernardes Jan 05 '15 at 20:59
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`kill -9 $(fuser 80/tcp 2>/dev/null)` – Hanynowsky Feb 11 '16 at 08:34

score 117 · Answer 2 · edited Dec 08 '21 at 23:43

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To kill a specific port in Linux use the below command

sudo fuser -k Port_Number/tcp

replace Port_Number with your occupied port.

edited Dec 08 '21 at 23:43

hmatar

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answered Jun 10 '15 at 10:03

Anil Chahal

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This actually kills the process that opened the port and not the port itself. – vinay chilakamarri May 26 '16 at 18:02

score 36 · Answer 3 · edited Apr 11 '22 at 10:32

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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

For MAC:

lsof -n -i :'port-number' | grep LISTEN

Sample Response :

java   4744 (PID)  test  364u  IP0 asdasdasda   0t0  TCP *:port-number (LISTEN)

and then execute :

kill -9 PID

Worked on Macbook

edited Apr 11 '22 at 10:32

alexkr

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answered Jun 29 '16 at 04:46

user2332505

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obviously this doesn't work if the PID column is empty for that port – Anentropic Sep 23 '16 at 17:08
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...and that happens if you don't have permission to see the process... try `sudo netstat` to actually see the PIDs :) – Anentropic Sep 23 '16 at 17:25
I was trying to kill a port on an amazon ec2 instance via putty cli. Forever said it had no processes running but the port(4200 for an angular app) was still open.This is the only command that worked for me. – vtechmonkey Oct 11 '17 at 20:07

score 20 · Answer 4 · edited Jul 31 '19 at 13:01

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To check all ports:

netstat -lnp

To close an open port:

fuser -k port_no/tcp

Example:

fuser -k 8080/tcp

In both cases you can use the sudo command if needed.

edited Jul 31 '19 at 13:01

Ferdi

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answered Jul 15 '19 at 11:55

Vinayak

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BEWARE: fuser kills the process not the port. Which means if the port's stuck in limbo, can it work at all? This is not the right answer. – Owl Sep 08 '21 at 00:51
Duplicate to the first two answers. – Cadoiz Dec 08 '21 at 12:53

score 19 · Answer 5 · answered Feb 27 '14 at 16:45

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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

answered Feb 27 '14 at 16:45

AlexT

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this just hangs `$ sudo tcpkill -9 port 5432 tcpkill: listening on lxcbr0 [port 5432]` – Anentropic Sep 23 '16 at 17:06

paxdiablo · Answer 6 · 2020-11-13T06:37:10.533

The "netstat --programs" command will give you the process information, assuming you're the root user. Then you will have to kill the "offending" process which may well start up again just to annoy you.

Depending on what you're actually trying to achieve, solutions to that problem will vary based on the processes holding those ports. For example, you may need to disable services (assuming they're unneeded) or configure them to use a different port (if you do need them but you need that port more).

score 6 · Answer 7 · answered Apr 15 '09 at 07:12

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

answered Apr 15 '09 at 07:12

Gleb

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netstat -anp|grep the last column has the process – user1747935 Jul 02 '15 at 16:59

score 1 · Answer 8 · answered Apr 15 '09 at 09:36

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.

This did not resolve my issue with ssh port forwarding. [`sudo fuser -k Port_Number/tcp`](https://stackoverflow.com/a/750705/4575793) did. — Cadoiz, Dec 08 '21 at 12:56

score -2 · Answer 9 · answered Apr 15 '09 at 07:12

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

answered Apr 15 '09 at 07:12

Tilo Prütz

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Zonxwedop · Answer 10 · 2013-07-18T13:06:02.827

-8

sudo killall -9 "process name"

edited Jul 18 '13 at 13:06

answered Mar 28 '13 at 19:23

Zonxwedop

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score -14 · Answer 11 · answered Jul 18 '13 at 13:04

-14

Shutting down the computer always kills the process for me.

answered Jul 18 '13 at 13:04

Zonxwedop

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shutting down a server machine is rare. – waqas Oct 09 '14 at 15:34
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did you get your "funniest" badge ? – jplandrain Mar 19 '15 at 14:51
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No need for shutting down your computer. – Anil Chahal Sep 16 '15 at 08:16
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Best idea ever 10/10 – Valentin Roudge Jan 27 '16 at 13:06
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unlike some of the other answers, this will surely work – Anentropic Sep 23 '16 at 17:06
-14 votes damn that must be a world record – Sandu Chicu Jul 23 '23 at 16:43

Freeing up a TCP/IP port?

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