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Python - [Errno 111] Connection refused on client side of the connection

I'm trying to create a chat between client and server written in Python, using SSL protocols with mutual authentication (i.e: server authenticates client and client authenticates server using certificates). My host machine is being used as the server, and my laptop is the client.
When attempting to connect to my host ip, I keep getting this error on my laptop:
Traceback (most recent call last):
File "/home/icarus/Codes/RealtimeChat/Chat.py", line 88, in <module>
main()
File "/home/icarus/Codes/RealtimeChat/Chat.py", line 75, in main
connection(ip, port, SSLSock)
File "/home/icarus/Codes/RealtimeChat/Chat.py", line 35, in connection
sock.connect((ip, port))
File "/usr/lib/python3.10/ssl.py", line 1375, in connect
self._real_connect(addr, False)
File "/usr/lib/python3.10/ssl.py", line 1362, in _real_connect
super().connect(addr)
ConnectionRefusedError: [Errno 111] Connection refused
And in the server - which was supposed to print a message saying that a connection was refused - nothing happens, it keeps listening for connections as if nothing happened
Connection function on client side:
def connection(ip, port, sock):
try:
sock.connect((ip, port))
print(f"Connected with {ip}")
except Exception as e:
print("Connection failed: ", e)
sock.close()
Server side:
def acceptConnection(self):
while True:
con, senderIP = self.sock.accept()
# Attempting to wrap connection with SSL socket
try:
SSLSock = self.getSSLSocket(con)
# If exception occurs, close socket and continue listening
except Exception as e:
print("Connection refused: ", e)
con.close()
continue
print(f"{senderIP} connected to the server")
# Adding connection to clients list
self.clients.append(SSLSock)
# Initializing thread to receive and communicate messages
# to all clients
threading.Thread(target=self.clientCommunication, args=(SSLSock, ), daemon=True).start()
This is the main function on my server:
def main():
serverIP = "127.0.0.1"
port = int(input("Port to listen for connections: "))
server = Server()
server.bindSocket(serverIP, port)
server.socketListen(2)
server.acceptConnection()
Everything works fine when I connect from my localhost (e.g I open a server on my host machine on one terminal and use another one on the same machine to connect to it). Both machines have the required certificates to authenticate each other, so I don't think that's the problem. Also, without the SSL implementation, the connection between this two different computers was refused by the server
I've tried using sock.bind('', port) on server side, disabling my firewall, used telnet 127.0.0.1 54321 (on my host machine) to check if the connection was working on the specified port (and it is), and also on the client machine (which showed that the connection was refused). I also tried running both scripts with admin privileges (sudo), but it also didn't work. Any suggestions?

I found what was wrong: I was trying to connect to my public IP address (which I found by searching for "What is my ip" on Google), but instead what should be done is to connect to the private IP address (I guess that's the correct name), and you can see yours using ifconfig on Linux and Mac and ipconfig on Windows using a terminal. By doing this, I could connect two computers that are on my network to my desktop server, I still haven't tested for computers in different networks, but the problem has been solved.

simple socket programming exercise for TCP connections in Python; Error: "No connection could be made because the target machine actively refused it"

*Before you mark as duplicate please note that I am referencing this similar question found here:
Python Socket Programming - ConnectionRefusedError: [WinError 10061] No connection could be made because the target machine actively refused it
unfortunately but have found anything in that post that provides a solution to my problem.
I am working on a very basic exercise designed to familiarize students with programming related to networks. This particular assignment is a common one as is described as follows:
In this assignment, you will learn the basics of socket programming for TCP connections in Python: how to create a socket, bind it to a specific address and port, as well as send and receive an HTTP packet. You will also learn some basics of HTTP header format. You can only use Python3.
You will develop a web server that handles one HTTP request at a time. Your web server should accept and parse the HTTP request, get the requested file from the server’s file system, create an HTTP response message consisting of the requested file preceded by header lines, and then send the response directly to the client. If the requested file is not present in the server, the server should send an HTTP “404 Not Found” message back to the client.
Part one specification:
Put the attached HTML file (named HelloWorld.html) in the same directory in which the server webserver.py runs. Run the server program. Determine the IP address of the host that is running the server (e.g., 128.238.251.26 or localhost). From another host, open a browser and provide the corresponding URL. For example: http://128.238.251.26:6789/HelloWorld.html. You can open a browser in the same host where the server runs and use the following http://localhost:6789/HelloWorld.html.
‘HelloWorld.html’ is the name of the file you placed in the server directory. Note also the use of the port number after the colon. You need to replace this port number with the port number that was assigned to you. In the above example, we have used port number 6789. The browser should then display the contents of HelloWorld.html. If you omit “:6789”, the browser will assume port 80 (why?), and you will get the web page from the server only if your server is listening at port 80.
Then try to get a file that is not present on the server (e.g., test.html). You should get a “404 File Not Found” message.
Part Two specification:
Write your own HTTP client to test your server. Your client will connect to the server using a TCP connection, send an HTTP request to the server, and display the server response as an output. You can assume that the HTTP request sent is a GET method. The client should take command line arguments specifying the server IP address or hostname, the port at which the server is listening, and the HTTP file name (e.g., test.html or HelloWorld.html). The following is an input command format to run the client. webclient.py <server_host> <server_port>
My code is for the Webserver is as follows:
#import socket module
from socket import *
import sys # In order to terminate the program
serverSocket = socket(AF_INET, SOCK_STREAM)
# Prepare a sever socket
# Fill in start
serverHost = '192.168.1.4'
serverPort = 56014
serverSocket.bind((serverHost, serverPort))
serverSocket.listen(5)
# Fill in end
while True:
#establish connection
print('The server is ready to receive')
connectionSocket, addr = serverSocket.accept() # Fill in start #Fill in end
try:
message = connectionSocket.recv(4096) # Fill in start #Fill in end
filename = message.split()[1]
f = open(filename[1:])
outputdata = f.readlines() # Fill in start #Fill in end
# send one http header line in to the socket
# Fill in start
connectionSocket.send("HTTP/1.1 200 OK\r\nContent-Type: text/html\r\n")
connectionSocket.send("\r\n")
# Fill in end
# Send the content of the requested file to the connection socket
for i in range(0, len(outputdata)):
connectionSocket.send(outputdata[i].encode())
connectionSocket.send("\r\n".encode())
connectionSocket.close()
except IOError:
# Send HTTP response code and message for file not found
# Fill in start
connectionSocket.send("HTTP/1.1 404 Not Found\r\n")
connectionSocket.send("Content-Type: text/html\r\n")
connectionSocket.send("\r\n")
connectionSocket.send("<html><head></head><body><h1>404 Not Found</h1></body></html><\r\n>")
# Fill in end
# Close the client connection socket
# Fill in start
serverSocket.close()
# Fill in end
serverSocket.close()
sys.exit() # Terminate the program after sending the corresponding data
My code for the Webclient is as follows:
from socket import *
import sys
serverName = sys.argv[1]
serverPort = int(sys.argv[2])
fileName = sys.argv[3]
request = "GET "+str(fileName)+" HTTP/1.1"
clientSocket = socket(AF_INET, SOCK_STREAM)
clientSocket.connect((serverName, serverPort))
clientSocket.send(request.encode())
returnFromSever = clientSocket.recv(4096)
while(len(returnFromSever)>0):
print(returnFromSever.decode())
returnFromSever = clientSocket.recv(4096)
clientSocket.close()
The error I am receiving is:
"No connection could be made because the target machine actively refused it"
Admittedly, I know almost nothing about network related programming and on top of that I am not familiar with the Python syntax (my entire degree program was exclusively in Java) so I am very lost here and somewhat desperate.
If anyone could please point me in the right direction as far as how to correct this error, I would be very deeply grateful.
Thanks

The error you are getting (No connection could be made because the target machine actively refused it) means that the port you are trying to connect to is not not being listened on the server.
For example, if you try to connect to 192.168.1.1:80 (IP = 192.168.1.1, port=80) and the server on 192.168.1.1 doesn't listen on port 80, you would receive this error.
A few things I would check in your case:
Is your server IP actually 192.168.1.4 ? If not, set it to the correct IP of the interface you want to listen on. If you want to listen on all the interfaces of the server, use this: serverHost = '0.0.0.0'
Does your client code attempt to connect to the server port? The server port is 56014. You need to pass it as the second parameter of your client program (because of this line serverPort = int(sys.argv[2])).

How to connect client in a internet to the server

I made a simple chat room. But I can't connect clients who joined through internet. I know I'm using local network to this program. But I researched how to connect my server to the internet. I used my Dynamic public IP and port forwarded using my router, but It didn't work. And I used ngrok, but it also didn't work. How can I solve this problem.
This is a part of my program.
IP_Address = 'IP'
Address = (IP_Address,PORT)
server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
server.bind(Address) # Bind IP address and Port to this socket.
When I used my public addressit shows this error.
Traceback (most recent call last):
File "Documents/Projects/Python/server.py", line 13, in <module>
server.bind(Address) # Bind IP address and Port to this socket.
OSError: [Errno 99] Cannot assign requested address

Use server.bind(('',port)) or server.bind(('0.0.0.0',port)). Both mean "bind to all interfaces".
If you want to bind to a specific interface, use your local IP, not the public one. Use ipconfig from the console to see your IP address.
On the router, forward the port to your local IP. Clients on the internet connect to your public IP and port.

I think the best way to solve this problem is using a Cloud Application Platform to run the server program.

Create TCP Server accessible on remote networks

A project I am working on has an Android app as a front-end and a Python program that would be used as the back-end.
I want to send data from the Android app (primarily images) to the Python program, do some processing and send the result back to the Android app.
I have found numerous tutorials that suggest using the socket module in python to create the server side, but all tutorials show the server on local network only (For testing purposes I created the client side also in Python, but it would be converted to Java later on)
The server code:
from requests import get
import socket
public_ip = get('https://api.ipify.org').text
print('My public IP address is: {}'.format(public_ip))
# getting the hostname by socket.gethostname() method
hostname = socket.gethostname()
# getting the IP address using socket.gethostbyname() method
local_ip = socket.gethostbyname(hostname)
# printing the hostname and ip_address
print(f"Hostname: {hostname}")
print(f"IP Address: {local_ip}")
#
HOST = local_ip
PORT = 80 # Port to listen on (non-privileged ports are > 1023)
with socket.socket(family=socket.AF_INET, type=socket.SOCK_STREAM, proto=0) as s:
s.bind((HOST, PORT))
s.listen()
conn, addr = s.accept()
with conn:
print('Connected by', addr)
while True:
data = conn.recv(1024).decode('utf-8')
if not data:
break
conn.sendall(data.encode('utf-8'))
The client code:
import socket
HOST = '…' # I modify it to the server's public IP address, as printed from the server code
PORT = 80 # The port used by the server
with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
with socket.create_connection((HOST, PORT)) as s:
s.sendall(b'Hello, world')
data = s.recv(1024)
print('Received', repr(data))
Using the code above, if I try using any port other than 80 I get ConnectionRefusedError: [Errno 111] Connection refused. And for port 80, I get TimeoutError: [Errno 110] Connection timed out.
In both cases, I try to connect from a device on another network.
I tried to use the ping command in Windows CMD to check the connection to the server, and I get 'connection refused message'.
I understand that the Firewall is what probably blocks the connection, but I don't know how to bypass it. I added a new rule in the Inbound Rules section (as suggested on other websites) but for no avail… The results were the same.
How can I make the connection between remote devices on different networks?
Thanks in advance ☺

In order to connect to your server using a TCP socket connection, you need to make sure your server can listen on a port on a publically available IP address.
If the External IP address is assigned to your computer directly,
and if you run the server code on that computer, then the TCP port opened by the server code should be available on the internet.
However, IP addresses are often assigned to a modem/router in home networks,
instead of assigning them to any connected device directly.
To find out if your External IP address is assigned to the computer directly you can use tools that your OS support (eg. ipconfig on windows). If you can see the IP address returned by api.ipify.org, then it means your computer is connected directly. You can change your code to connect using publically exposed IP:
HOST = public_ip
If this is successful means your computer is assigned an external address directly. Which is highly unlikely.
There are several workarounds for this problem though:
1) Configure your router to forward port
Configure your router to forward all connections to it's external TCP port, to an internal host in your network which is assigned to your computer. Please find instructions how it is done for your router.
2) Setup a remote proxy
If you don't have permission to change your router settings you can set up a remote proxy listening on the TCP port. While there is a number of ways of doing this, very popular is to set up a remote SSH tunnel, for that you need to have a server with SSH access and an external IP. Run this command:
ssh -R 80:localhost:8080 root#your-ssh-server-host
You can also use a third-party service that exposes your private host on the internet like:
Ngrok (Commercial, with free plans)
Localtunnel (Open Source, can be self-hosted)

Why am I getting a ConnectionResetError for my basic python UDP client?

I'm on a 2020.4 Kali Linux VM on VMWare Workstation 16 Player and I'm working with the Black Hat Python book by Justin Seitz. Right in the beginning of Chapter 2 he introduces a basic UDP client but for some reason, I get thrown a ConnectionResetError every time because either the port I'm sending to or the port I'm receiving from is occupied. I then added a line to make it bind to the address I'm sending to and it worked. Is it not automatically binding when I sendto()? If I'm pentesting, I shouldn't need the password/admin to bind when I make a UDP client.
Here is my code:
import socket
address = ('127.0.0.1', 80)
# Create a socket object.
client = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
# I commented this out just for testing reasons.
# client.bind(address)
# Send some data.
client.sendto(b'AAABBBCCC', address)
# Receive some data.
data, addr = client.recvfrom(4096)
print(data)
Here's the error:
Traceback (most recent call last):
File ".\udp_client.py", line 15, in <module>
data, addr = client.recvfrom(4096)
ConnectionResetError: [WinError 10054] An existing connection was forcibly closed by the remote host
I apologize in advance if this is some dumb mistake on my part.
EDIT:
I changed the code to use a different port (65536) yet now it just doesn't print anything or end the script, it just keeps running.

I'd suggest you try using a port other than port 80 (default for all HTTP traffic) which is likely being used constantly and isn't a good port to try and hold onto, try port numbers > 1023