I get this error:' socket.gaierror: [Errno 11001] getaddrinfo failed' when I use the socket module in python

Question

So I am making a simple script which just sends messages from a client to the server. When the client and the server is on the same computer, the script runs perfectly but when I use another laptop and try to send a message to the server it shows this error on the client laptop.

server script:

import threading


HEADER = 64
PORT = 5000
SERVER = '######'
ADDR = ('', PORT)
FORMAT = 'utf-8'
DISCONNECT_MSG = '//*DISCONNECT*//'

server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
server.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
server.bind(ADDR)



def handle_client(conn, addr):
    print(f'[NEW CONNECTION] {addr}')
    connected = True
    while connected:
        msg_len = conn.recv(HEADER).decode(FORMAT)
        if msg_len:
            msg_len = int(msg_len)
            msg = conn.recv(msg_len).decode(FORMAT)
            if msg == DISCONNECT_MSG:
                connected = False
            print(f'[{addr}] {msg}')
    conn.close()
    
    


def start():
    print(f'[LISTENING] listening on {SERVER}')
    server.listen()
    while True:
        conn, addr = server.accept()
        # hc for hand client
        thread_hc = threading.Thread(target=handle_client, args=(conn, addr))
        thread_hc.start()
        print(f'[ACTIVE CONNECTIONS] {threading.activeCount() - 1}')


print('[STARTING] server is starting.....')
start()

client script:

HEADER = 64
PORT = 5000
FORMAT = 'utf-8'
DISCONNECT_MSG = '//*DISCONNECT*//'
SERVER = '######'
ADDR = (SERVER, PORT)

client = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
client.connect(ADDR)

def send(msg):
    message = msg.encode(FORMAT)
    msg_length = len(message)
    send_length = str(msg_length).encode(FORMAT)
    send_length += b' ' * (HEADER - len(send_length))
    client.send(send_length)
    client.send(message)

try:
    while True:
        msg = input('message: ')
        send(msg)
        if msg == DISCONNECT_MSG:
            break
except BrokenPipeError:
    print('the connection was broken')

Can you tell me what is the problem in the code. I am new to sockets in python, so if I am making any rookie mistakes, please overlook it.

Answer 1

getaddrinfo failed is an error that means the OS couldn't resolve an IP address for a DNS name.

For example, if SERVER is a-name-with-no-ip.example.com and you try to connect to it, it will throw a getaddrinfo failed .