Python [Errno 98] Address already in use

Question

In my Python socket program, I sometimes need to interrupt it with Ctrl-C. When I do this, it does close the connection using socket.close().

However, when I try to reopen it I have to wait what seems like a minute before I can connect again. How does one correctly close a socket? Or is this intended?

score 159 · Accepted Answer · edited Jul 14 '23 at 05:05

159

Yes, this is intended. Here you can read a detailed explanation. It is possible to override this behavior by setting the SO_REUSEADDR option on a socket. For example:

sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)

edited Jul 14 '23 at 05:05

eoirqgfoqkrognoqwfr

3
2

answered Dec 16 '10 at 22:33

Bartosz

6,055
3
27
17

Strange. I've called this right before binding and the error is still occurring. I must be making a mistake somewhere else. – byxor Feb 08 '17 at 10:25
Nevermind, I had a bizarre race condition when repeatedly binding and shutting down on separate threads for my automated tests. – byxor Feb 08 '17 at 14:16
You need to import module called socket. – Bartosz Jun 16 '20 at 19:19
6

IMPORTANT NOTE: `sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)` works, BUT you should use that right after you create the socket. It will not work after `.bind()`! – vlad-ardelean Jun 26 '21 at 16:22
where do you set this? Inside python? bash? – thistleknot Dec 26 '21 at 17:01
@thistleknot No, in your code. For example: `udp = socket.socket(socket.AF_INET, / socket.SOCK_DGRAM) / udp.bind((UDP_IP, UDP_PORT)) / udp.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)` (/ is a new line) – Domkrt Dec 27 '21 at 18:03

score 65 · Answer 2 · edited Mar 20 '18 at 14:11

65

$ ps -fA | grep python
501 81211 12368   0  10:11PM ttys000    0:03.12  
python -m SimpleHTTPServer

$ kill 81211

edited Mar 20 '18 at 14:11

phoenix

7,988
6
39
45

answered Jun 13 '16 at 13:58

ayoub laaziz

1,196
9
12

6

Unfortunately, it doesn't always work. This was my immediate thought when I ran into this problem, but there is no python process to kill in my case. – Kryten Dec 18 '16 at 05:14
2

@Kryten use Kill -9 81211 – R.singh Nov 01 '21 at 11:55
[Do not use kill -9](https://unix.stackexchange.com/questions/8916/when-should-i-not-kill-9-a-process). It wouldn't work in this case anyway as the user stated that there is no python process to kill. – SupBrah Sep 20 '22 at 17:43

MohitGhodasara · Answer 3 · 2021-07-06T09:23:06.807

This happens because you trying to run service at the same port and there is an already running application. it can happen because your service is not stopped in the process stack. you just have to kill those processes.

There is no need to install anything here is the one line command to kill all running python processes.

for Linux based OS:

Bash:

kill -9 $(ps -A | grep python | awk '{print $1}')

Fish:

kill -9 (ps -A | grep python | awk '{print $1}')

score 27 · Answer 4 · edited Aug 12 '21 at 05:33

27

If you use a TCPServer, UDPServer or their subclasses in the socketserver module, you can set this class variable (before instantiating a server):

socketserver.TCPServer.allow_reuse_address = True

(via SocketServer.ThreadingTCPServer - Cannot bind to address after program restart )

This causes the init (constructor) to:

 if self.allow_reuse_address:
     self.socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)

edited Aug 12 '21 at 05:33

ntc2

11,203
7
53
70

answered Aug 27 '14 at 14:17

dirkk0

2,460
28
34

where do you set this? Inside python? bash? – thistleknot Dec 26 '21 at 17:00

score 16 · Answer 5 · answered Jul 15 '18 at 11:57

16

A simple solution that worked for me is to close the Terminal and restart it.

answered Jul 15 '18 at 11:57

Siddharth Sethia

169
1
3

score 14 · Answer 6 · edited Jan 28 '20 at 08:33

14

Nothing worked for me except running a subprocess with this command, before calling HTTPServer(('', 443), myHandler):

kill -9 $(lsof -ti tcp:443)

Of course this is only for linux-like OS!

edited Jan 28 '20 at 08:33

Areza

5,623
7
48
79

answered May 22 '17 at 10:50

Mirko

757
9
13

score 11 · Answer 7 · edited Oct 29 '21 at 05:32

11

For Linux,

ps aux | grep python

This will show you the error. The process number (eg.35225) containing your python file is the error.

Now,

sudo kill -9 35225

This will kill the error process and your problem will be solved.

edited Oct 29 '21 at 05:32

Prajwal Kulkarni

1,480
13
22

answered Oct 28 '21 at 15:25

Tribhuwan Bhatta

111
1
2

score 8 · Answer 8 · answered Apr 28 '20 at 11:27

8

First of all find the python process ID using this command

ps -fA | grep python

You will get a pid number by naming of your python process on second column

Then kill the process using this command

kill -9 pid

answered Apr 28 '20 at 11:27

Abdul Basit

953
13
14

score 3 · Answer 9 · edited Mar 04 '20 at 13:02

3

run the command

fuser -k (port_number_you_are _trying_to_access)/TCP

example for flask: fuser -k 5000/tcp

Also, remember this error arises when you interput by ctrl+z. so to terminate use ctrl+c

edited Mar 04 '20 at 13:02

mischva11

2,811
3
18
34

answered Mar 04 '20 at 12:39

Manoj Kumar M

31
1

This doesn't quite work if the process that used that port is already dead :q – SasQ Mar 28 '21 at 10:37

score 2 · Answer 10 · answered Jun 02 '21 at 06:37

I faced similar error at odoo server and resolved that with these simple following steps:

Paste following code in terminal

ps -fA | grep python

You will get a pid number. Now copy the pid number from second column of terminal output.

Then write as below

kill -9 pid

The terminal will restart and then the command

flask run

Will work fine! Thank you

score 2 · Answer 11 · answered Nov 13 '21 at 11:22

2

Do nothing just wait for a couple of minutes and it will get resolved. It happens due to the slow termination of some processes, and that's why it's not even showing in the running processes list.

answered Nov 13 '21 at 11:22

Shoaib Alam

31
2

score 0 · Answer 12 · answered May 31 '21 at 22:50

I had the same problem (Err98 Address already in use) on a Raspberry Pi running python for a EV charging manager for a Tesla Wall Connector. The software had previously been fine but it stopped interrogating the solar inverter one day and I spent days thinking it was something I'd done in python. Turns out the root cause was the Wifi modem assigning a new dynamic IP to the solar inverter as as result of introducing a new smart TV into my home. I changed the python code to reflect the new IP address that I found from the wifi modem and bingo, the issue was fixed.

score 0 · Answer 13 · answered Jul 10 '22 at 15:31

0

Got this error after I ran my code while programming a Pico W via Thonny. At the command line just do a socket.reset() to clear the issue.

>>> socket.reset()

answered Jul 10 '22 at 15:31

Clarius

1,183
10
10

Ate Somebits · Answer 14 · 2022-09-13T14:31:11.520

The cleanest way to make the socket immediately reusable is to follow the recommendation to first shutdown the client end (socket) of a connection, and make sure the server's end shuts down last (through exception handling if needed).

This might well mean that the server end runs forever.

This is not a problem if that "forever" loop pauses execution, e.g. read from socket.

How you "break" that "forever" loop is up to you as server admin, as long as there are no clients (apart from obvious system level exceptions)

score 0 · Answer 15 · answered Dec 06 '22 at 23:38

0

I tried the following code to settle the issue:

sudo lsof -t -i tcp:8000 | xargs kill -9

answered Dec 06 '22 at 23:38

Jalil Nourmohammadi Khiarak

418
6
10

score -3 · Answer 16 · answered May 27 '21 at 12:17

-3

sudo pkill -9 python

try this command

answered May 27 '21 at 12:17

Sahil Rajput

9

5

Despite this being technically a possible solution to the problem here, I don't think this is a good idea to simply kill all python processes. What if you have some other processes that need python to work properly? You would kill all of them. – bastantoine May 27 '21 at 19:21

Python [Errno 98] Address already in use

16 Answers16

Linked

Related