Connection error errno 111 connection refused

1. Why the ConnectionRefusedError: [Errno 111] Connection refused Occurs in Python
2. How to Solve the ConnectionRefusedError: [Errno 111] Connection refused in Python
3. Conclusion

This error indicates that the client cannot connect to the port on the server script’s system. Since you can ping the server, it should not be the case.

This might be caused by many reasons, such as improper routing to the destination. The second possibility is that you have a firewall between your client and server, which may be either on the server or the client.

There shouldn’t be any routers or firewalls that may stop the communication since, based on your network addresses, both the server and the client should be on the same Local Area Network.

Why the ConnectionRefusedError: [Errno 111] Connection refused Occurs in Python

This error arises when the client cannot access the server because of an invalid IP or port or if the address is not unique and used by another server.

The connection refused error also arises when the server is not running, so the client cannot access the server as the server should accept the connection first.

Code example:

# server code
import socket

s = socket.socket()
host = socket.gethostname()
port = 1717
s.bind((host, port))

s.listen(5)
while True:
    c,addr = s.accept()
    print("Got connection ", addr)
    c.send("Meeting is at 10am")
    c.close()

# client code
import socket

s = socket.socket()
host = '192.168.1.2'
port = 1717

s.connect((host,port))
print(s.recv(1024))
s.close

Output:

socket.error: [Errno 111] Connection refused

How to Solve the ConnectionRefusedError: [Errno 111] Connection refused in Python

Try to keep the receiving socket as accessible as possible. Perhaps accessibility would only take place on one interface, which would not impact the Local Area Network.

On the other hand, one case can be that it exclusively listens to the address 127.0.0.1, making connections from other hosts impossible.

Code example:

import socket

s = socket.socket()
host = socket.gethostname()
port = 1717
s.bind(('', port))

s.listen(5)
while True:
    c,addr = s.accept()
    print("Got connection ", addr)
    c.send("The Meeting is at 10 am")
    c.close()

import socket

s = socket.socket()
host = socket.gethostname()
port = 1717
s.bind(('', port))

s.connect((host, port))
print(s.recv(1024))
s.close()

Output:

Got connection('192.168.1.2')
The meeting is at 10 am

When you run the command python server.py, you will receive the message Got connection. At the same time when you run the command python client.py, you will receive a message from the server.

The DNS resolution can be the other reason behind this problem. Since the socket.gethostname() returns the hostname, an error will be returned if the operating system cannot translate it to a local address.

The Linux operating system can edit the host file by adding one line.

host = socket.gethostname()
port = 1717
s.bind((host,port))

Use gethostbyname

host = socket.gethostbyname("192.168.1.2")
s.bind((host, port))

Thus, you must use the identical technique on the client and server sides to access the host. For instance, you would apply the procedure described above in a client’s case.

You can also access through local hostname hostnamehost = socket.gethostname() or specific name for local host host = socket.gethostbyname("localhost").

host = socket.gethostname()
s.connect((host, port))

host = socket.gethostbyname("localhost")
s.connect((host, port))

Conclusion

ConnectionRefusedError in Python arises when the client cannot connect to the server. Several reasons include the client not knowing the IP or port address and the server not running when the client wants to connect.

There are several methods mentioned above to resolve this connection issue.

ConnectionRefusedError: [Errno 111] Connection Refused

This error indicates that the client cannot connect to the port on the server script’s system. Since you can ping the server, it should not be the case.

This might be caused by many reasons, such as improper routing to the destination. The second possibility is that you have a firewall between your client and server, which may be either on the server or the client.

There shouldn’t be any routers or firewalls that may stop the communication since, based on your network addresses, both the server and the client should be on the same Local Area Network.

Why the ConnectionRefusedError: [Errno 111] Connection refused Occurs in Python

This error arises when the client cannot access the server because of an invalid IP or port or if the address is not unique and used by another server.

The connection refused error also arises when the server is not running, so the client cannot access the server as the server should accept the connection first.

How to Solve the ConnectionRefusedError: [Errno 111] Connection refused in Python

Try to keep the receiving socket as accessible as possible. Perhaps accessibility would only take place on one interface, which would not impact the Local Area Network.

On the other hand, one case can be that it exclusively listens to the address 127.0.0.1 , making connections from other hosts impossible.

When you run the command python server.py , you will receive the message Got connection . At the same time when you run the command python client.py , you will receive a message from the server.

The DNS resolution can be the other reason behind this problem. Since the socket.gethostname() returns the hostname, an error will be returned if the operating system cannot translate it to a local address.

The Linux operating system can edit the host file by adding one line.

Use gethostbyname

Thus, you must use the identical technique on the client and server sides to access the host. For instance, you would apply the procedure described above in a client’s case.

You can also access through local hostname hostnamehost = socket.gethostname() or specific name for local host host = socket.gethostbyname(«localhost») .

Conclusion

ConnectionRefusedError in Python arises when the client cannot connect to the server. Several reasons include the client not knowing the IP or port address and the server not running when the client wants to connect.

There are several methods mentioned above to resolve this connection issue.

Zeeshan is a detail oriented software engineer that helps companies and individuals make their lives and easier with software solutions.

Источник

«socket.error: [Errno 111] Connection refused» while training on ADE20K #215

I am getting following error after few data iteration @ 551/22210:

File «train.py», line 201, in
trainer.training(epoch)
File «train.py», line 142, in training
for i, (data, target) in enumerate(tbar):
File «/usr/local/lib/python2.7/dist-packages/tqdm/_tqdm.py», line 930, in iter
for obj in iterable:
File «/usr/local/lib/python2.7/dist-packages/mxnet/gluon/data/dataloader.py», line 222, in next
return self.next()
File «/usr/local/lib/python2.7/dist-packages/mxnet/gluon/data/dataloader.py», line 218, in next
idx, batch = self._data_queue.get()
File «/usr/lib/python2.7/multiprocessing/queues.py», line 117, in get
res = self._recv()
File «/usr/local/lib/python2.7/dist-packages/mxnet/gluon/data/dataloader.py», line 88, in recv
return pickle.loads(buf)
File «/usr/lib/python2.7/pickle.py», line 1388, in loads
return Unpickler(file).load()
File «/usr/lib/python2.7/pickle.py», line 864, in load
dispatchkey
File «/usr/lib/python2.7/pickle.py», line 1139, in load_reduce
value = func(*args)
File «/usr/local/lib/python2.7/dist-packages/mxnet/gluon/data/dataloader.py», line 53, in rebuild_ndarray
fd = multiprocessing.reduction.rebuild_handle(fd)
File «/usr/lib/python2.7/multiprocessing/reduction.py», line 156, in rebuild_handle
conn = Client(address, authkey=current_process().authkey)
File «/usr/lib/python2.7/multiprocessing/connection.py», line 169, in Client
c = SocketClient(address)
File «/usr/lib/python2.7/multiprocessing/connection.py», line 308, in SocketClient
s.connect(address)
File «/usr/lib/python2.7/socket.py», line 228, in meth
return getattr(self._sock,name)(*args)
socket.error: [Errno 111] Connection refused

I am using latest nightly of MXNET along with Sync BatchNorm, This error comes with and without SyncBatchNorm layer.

I am using MXNET docker

Any help is much appreciated.

The text was updated successfully, but these errors were encountered:

Источник

ConnectionRefusedError: [Errno 111] Connection refused

I get «connection refused 111» when trying to communicate over sockets in Python. When the connection is refused, THE LISTENER STOPS LISTENING. Same problem occurs using import of multiprocessing.connection, socket, zeromq.

My feeling is that the link between Python and the OS/network doesn’t work. However the NC and socket commands issued in a ubuntu terminal can communicate over the same port.

Notwithstanding the inconvenience it’s causing me, there is obviously a severe security risk if an invalid connection request causes a socket to stop listening. Ideal for denial of service attacks.

I have two programs:

When I start the listener (f5 in IDLE), it seems to start ok.

and the socket starts listening:

ss -lt

State Recv-Q Send-Q Local Address:Port Peer Address:Port Process

LISTEN 0 1 192.168.1.100:16001 0.0.0.0:*

However, when I start the client (f5 in IDLE) I get this:

and the listening socket disappears.

ss -lt

State Recv-Q Send-Q Local Address:Port Peer Address:Port Process

LISTEN 0 5 127.0.0.1:ipp 0.0.0.0:* LISTEN 0 1 127.0.0.1:36093
0.0.0.0:*
LISTEN 0 5 [::1]:ipp [::]:*

Ive tried changing port numbers, setting FW rules, IP addresses from hard-coded to «localhost», . remote client (on Windows) etc etc. Nothing works although symptoms vary.

Ive tried programming the connection using the «socket import» and have exactly the same results. zeromq doesn’t work either.

However the NC and socket commands issued in a terminal can communicate over the same port.

fwiw Im running Ubuntu 20.04.2 LTS. Apart from the one client I tried on windows, all testing is done on a single ubuntu system. Its a fairly new install, so its unlikely I’ve broken something.

Please can someone tell me what I’m doing wrong?

My feeling is that the link between Python and the OS/network doesn’t work.

Notwithstanding the inconvenience it’s causing me, there is obviously a severe security risk if an invalid connection request causes a socket to stop listening. Ideal for denial of service attacks.

1 Answer 1

I couldn’t reproduce your issue, thus not sure what’s the problem. But, some remarks.

I added a simple ping-pong exchange to your code:

and also changed the listening address to one from the link-local subnet 127.0.0.0/8 .

Then simply using 2 terminal tabs/windows, run t2.py then t1.py 3 times:

The server process continues to run, as expected. The client tab:

Please pay attention. You may think these things you named are the same — but they are significantly different:

multiprocessing.connection, socket, zeromq.

The python-builtin import socket module is direct translation of the classic BSD sockets API. The «sockets API» is what defines such things as: port, listening on a port, connecting to a port, accepting a connection, send , recv , close and a few more functions. A book on network programming may help (e.g. this one as a random example — I don’t endorse it). The sockets API is almost 40 years old, so you’ll also easily find free learning materials online.

Next, import multiprocessing module. It’s a completely different story. It provides helpers for multi-process Python programs. Those create multiple PIDs and can run on multiple processor cores. Almost certainly you’ll want these processes to talk to each other to do useful work. This is where sockets come handy: since processes are isolated by OS from each other, network provides a way to build that communication (even if it’s localhost-only). The sub-module multiprocessing.connection provides ergonomic helpers exactly for that.

Next, ØMQ is altogether a separate project (it’s not python-builtin; neither it’s python-specific). It does something interesting; it redefines another «socket API». ØMQ socket ≠ BSD socket. Zeromq sockets can do things which BSD sockets can’t (pub/sub, fanout, app-level routing). Zeromq sockets are built «on top of» BSD sockets; if you have troubles with the lower-level API, I would recommend to approach ZMQ only after you get comfortable with bare basic sockets.

Nothing works although symptoms vary.

Again, you should get comfortable with interpreting network failure modes. The raised error codes have precisely defined meanings. For example, the classic Connection refused errno 111 means that the initial SYN packet to the host you connect() to was responded with an RST packet instead of the normal SYN+ACK — which usually happens when there’s no program listening to the given port on the remote computer you connect() to.

One more remark with regards to your security concerns. You should always assume that the network is adversarial (hostile), regardless if it’s indeed true at that point in space & time — even the localhost network. This is why the higher-level multiprocessing API has the authkey parameter; it’s practically always needed. The password bytestring is one of the worst values for authkey imaginable, try something better. An active network adversary could, theoretically, explain your issue; there’s something called «RST injection attack». You might’ve simply exhausted the listen backlog/SOMAXCONN, too.

Источник

socket.error: [Errno 111] Connection refused [JIRA: CLIENTS-41] #375

I am using RIAK Python client for my project and RIAK amazon instance.I got this error while running my project and its related to RIAK instance.My error log is :-
Traceback (most recent call last):
File «ironjob/ai/index.py», line 36, in application
returnval = mManager.process(api)
File «ironjob/ai/ironMainManager.py», line 94, in process
return self.mUserManager.process(listitem)
File «ironjob/ai/ironUserManager.py», line 27, in process
return self.userVerification(listitem)
File «ironjob/ai/ironUserManager.py», line 62, in userVerification
self.mCacheManager.addData(BUCKET_AI, datadict[KEY_SESSID], sessionData, cacheStart=1, cacheEnd=3, timeout=60)
File «ironjob/ai/ironCacheManager.py», line 55, in addData
self.mRiakClient.addData(bucket, key, dataVals, nestedKey=innerKey, timeout=timeout)
File «ironjob/ai/ironRiakClient.py», line 53, in addData
currentData = <> if bucket.get(key).get_data() == None else bucket.get(key).get_data()
File «build/bdist.linux-x86_64/egg/riak/bucket.py», line 326, in get
File «build/bdist.linux-x86_64/egg/riak/riak_object.py», line 459, in reload
File «build/bdist.linux-x86_64/egg/riak/transports/pbc.py», line 251, in get
File «build/bdist.linux-x86_64/egg/riak/transports/feature_detect.py», line 76, in quorum_controls
File «build/bdist.linux-x86_64/egg/riak/util.py», line 61, in get
File «build/bdist.linux-x86_64/egg/riak/transports/feature_detect.py», line 95, in server_version
File «build/bdist.linux-x86_64/egg/riak/transports/pbc.py», line 178, in _server_version
File «build/bdist.linux-x86_64/egg/riak/transports/pbc.py», line 206, in get_server_info
File «build/bdist.linux-x86_64/egg/riak/transports/pbc.py», line 528, in send_msg_code
File «build/bdist.linux-x86_64/egg/riak/transports/pbc.py», line 559, in send_pkt
File «build/bdist.linux-x86_64/egg/riak/transports/pbc.py», line 113, in maybe_connect
File «build/bdist.linux-x86_64/egg/riak/transports/connection.py», line 166, in maybe_connect

File «», line 1, in connect
socket.error: [Errno 111] Connection refused

Please help me out.Thanks in advance.

The text was updated successfully, but these errors were encountered:

Connection refused means exactly what it says. Whatever port you tried to connect to, the Riak server is not listening on or is otherwise inaccessible. Possible causes/solutions:

Источник

connect() failed (111: Connection refused) while connecting to upstream

I’m experiencing 502 Gateway errors when accessing a PHP file in a directory ( http://example.com/dev/index.php ). The logs simply says this:

I’ve never experienced this before. What is the solution for this type of 502 Gateway error?

This is the nginx.conf :

8 Answers 8

It sounds like you haven’t started and configured the backend for Nginx. Start php-fpm and add the following to nginx.conf , in the http context:

This answer is only for those who get an error like this:

connect() failed (111: Connection refused) while connecting to upstream, client . fastcgi://[::1]:9000

Rewrite your nginx config to use ip, not dns. For instance, 127.0.0.1 instead of localhost , or remove the ipv6 alias from /etc/hosts.

Got errors like this too. Problem was my abstract backend referencing two servers. php-fpm was only listing to socket.

Had the same problem with proxied requests to a Node server listening on port 5000. Requests would result with 200 OK but sometime 502 Bad Gateway randomly. NGINX showed the error:

1. Set node HTTP server to listen strictly for ipv4 by including localhost as host: server.listen(5000, ‘localhost’);
2. Removed any ipv6 listen directives ( listen [::]:80; or listen [::]:443 ssl default_server; ).
3. Changed location block proxy_pass to use IPs: proxy_pass http://127.0.0.1:5000 (not proxy_pass http://localhost:5000 ).

Hope this helps someone.

In my case the error was a bad location for the error_log file for php5.6-fpm service and thus the php-fpm service was failing to start and nginx was not able to connect to it. You can find it in /etc/php/5.6/fpm/php.ini (you can replace 5.6 with the version you are running).

Same problem has occured for me and finally I found firewalld was blocking required ports after installation and I was missing to open ports in firewall (port 9000 in your logs).

Just in case somebody is deperately trying to fix their problem just to realize there is nothing wrong with their reverse proxy setup:

In my case, the error persisted even after I’ve removed all location directives but a single one that only provides static content.

The error message was caused because Nginx wasn’t able to log it’s log to the syslog server:

Summary:

If you are using a syslog log server, make sure it is available. To test whether the error originates from the logging setup, comment out all logging configs so that Nginx falls back to the native logging scheme.

I hope this saves some people time debugging a fully valid reverse proxy config, just to fid the error somewhere else 😀

Источник

In this post, we are going to show you how to solve «Unhandled Exception: DioError [DioErrorType.other]: SocketException: OS Error: Connection refused, errno = 111, address = localhost, port = 51746» Error in Flutter App. 

E/flutter (16776): [ERROR:flutter/lib/ui/ui_dart_state.cc(209)] 
Unhandled Exception: DioError [DioErrorType.other]: 
SocketException: OS Error: Connection refused, errno = 111, 
address = localhost, port = 51746
E/flutter (16776): Source stack:
E/flutter (16776): #0      DioMixin.fetch (package:dio/src/dio_mixin.dart:473:35)
E/flutter (16776): #1      DioMixin.request (package:dio/src/dio_mixin.dart:468:12)
E/flutter (16776): #2      DioMixin.get (package:dio/src/dio_mixin.dart:55:12)

Here, you can clearly see «address = localhost», which means you are accessing the URL on localhost, but you are getting the error. See the examples below to solve this issue.

«localhost» is not identified domain name or has no DNS record, therefore, your emulator is not getting the actual IP address to the localhost server from the Mobile app or from Emulator, for example, let’s try to access the address from «Chrome» browser on Mobile/Emulator:

To solve this error, use a local IP address instead of «localhost» in your Flutter/Dart code, and also be careful if WAMP or XAMPP is running? For example:

Response response = await dio.get("http://localhost/test/data.php"); 
//Connection refused error,

Change this to:

Response response = await dio.get("http://192.168.0.235/test/data.php"); 
//use local IP or actual live URL

Here, We have used the local IP address of the local server, or you can also use the Live URL if API is hosted in the live server.

And also be careful, here you are using «HTTP» instead of secure «HTTPS» protocol, you may get the error, see this link: How to Solve ’Insecure HTTP is not allowed by platform’ Error 

For Windows User:

ipconfig

//output:  IPv4 Address. . . . . . . . . . . : 192.168.0.235

For Linux User:

ip a

for Mac OS Users:

ipconfig getifaddr en1 
//for wired connection 

ipconfig getifaddr en0
//for wifi connection

In this way, you can solve the «Unhandled Exception: DioError [DioErrorType.other]: SocketException: OS Error: Connection refused» error for Localhost address in your Flutter App.

I’m a beginner to socket programming. I’m trying to develop a TCP based client server framework where one server needs to connect with multiple clients. This works when I’m running both the scripts on my computer. It fails with the following error when I run the client.py script in my friend’s computer, or when I’m running server.py online on pythonanywhere:

 File "client.py", line 9, in <module>
    s.connect((host, port))
 ConnectionRefusedError: [Errno 111] Connection refused

Here’s what my client.py looks like :

import socket
import os
import subprocess

s = socket.socket()
host = 'client.ip.address'
port = 9999

s.connect((host, port))

while True:
    data = s.recv(1024)
    if data[:2].decode("utf-8") == 'cd':
        os.chdir(data[3:].decode("utf-8"))

    if len(data) > 0:
        cmd = subprocess.Popen(data[:].decode("utf-8"),shell=True, stdout=subprocess.PIPE, stdin=subprocess.PIPE, stderr=subprocess.PIPE)
        output_byte = cmd.stdout.read() + cmd.stderr.read()
        output_str = str(output_byte,"utf-8")
        currentWD = os.getcwd() + "> "
        s.send(str.encode(output_str + currentWD))

        print(output_str)

My server.py looks like this. Here’s a part of it :

# Create worker threads
def create_workers():
    for _ in range(NUMBER_OF_THREADS):
        t = threading.Thread(target=work)
        t.daemon = True
        t.start()


# Do next job that is in the queue (handle connections, send commands)
def work():
    while True:
        x = queue.get()
        if x == 1:
            create_socket()
            bind_socket()
            accepting_connections()
        if x == 2:
            start_turtle()

        queue.task_done()


def create_jobs():
    for x in JOB_NUMBER:
        queue.put(x)

    queue.join()


create_workers()
create_jobs()

And yes, I always execute my server script before client script. How should I resolve this error?