[SOLVED] ConnectionRefusedError when trying to host python socket server on raspberry pi

Issue

I'm trying to make a basic python networking program. All I'm trying to do is send strings of text back and forth between the server and the client. I'm trying to host the server on my Raspberry Pi, and connect with a client on Windows 10. The program works great locally on my computer, but when I try to connect to my server, it gives me ConnectionRefusedError: [WinError 10061] No connection could be made because the target machine actively refused it. My server code is as follows:

import socket               # Import socket module
import netifaces as ni

s = socket.socket()         # Create a socket object
host = socket.gethostname() # Get local machine name
port = 12345                # Reserve a port for your service.

s.bind((host, port))

#host_ip = ni.ifaddresses('wlan0')[ni.AF_INET][0]['addr']

host_ip = "bruh?"

print("Server started! \nHostname: " + host + " \nIP: " + host_ip + " \nPort: " + str(port))

s.listen()                  # Now wait for client connection.
while True:
   c, addr = s.accept()     # Establish connection with client.
   print('Got connection from', addr)
   output = "Welcome to the server!".encode()
   c.send(output)

   c.close()

Client code:

import socket

s = socket.socket()

host = 192.168.1.21
port = 12345

s.connect((host, int(port)))

noResponse = False
serverResponse = s.recv(1024).decode()
    
print(serverResponse)
    
s.close()

Does anyone know what my problem is? Thanks.

Solution

There may be a few reasons you are getting a ConnectionRefusedError, please try the following:

1. Check that no firewall is blocking your connection.
2. Double-check the server IP, if it is wrong you may get this error.
3. Try to use Hercules to check the connection.

Also, I would change the code as follow:

Server:

import socket

HOST = ''  # localhost
PORT =     # IMPORTANT !! Do not use reserved ports 

with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as sock:
    sock.bind((HOST, PORT))
    sock.listen()
    conn, addr = sock.accept()
    with conn:
        print('Connected by', addr)
        while True:
            data = conn.recv(1024)
            if not data:
                break
            print('Data: ',data)
            conn.sendall('RT') 

Client:

import socket

HOST = ''  # server IP address
PORT =     # server port

with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as sock:
    sock.connect((HOST, PORT))
    sock.sendall('Hello, I am the Client')
    data = sock.recv(1024)

print('Received', data)

By doing this you are using a TCP connection and you can test your code with different TCP server and client emulators.

Answered By - Mateo Lara