Win Error 10061 No connection could be made because the target machine actively refused it-CodePudding

I have been experimenting with the socket library for python. I made a simple program for the server and client where the client can message the server.

Here is my code for the server:

import socket

print("Host")

socket_main = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
socket_main.bind(('127.0.0.1', 9999))

socket_main.listen(1)
conn, addr = socket_main.accept()

while True:
    data = conn.recv(1204).decode()
    print(data)

conn.close()

Here is my code for the client

import socket

print("Client")

socket_main = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
socket_main.connect(('127.0.0.1', 9999))

while True:
    message = input(": ")
    socket_main.send(message.encode())

socket_main.close()

When I run these programs in two different terminals on one computer it works just fine, but when I try to run the server and client on different computers I get an error on the clients end saying, "No connection could be made because the target machine actively refused it".

I have tried changing the port multiple times but it didn't help. I have looked through a lot of other forums and I haven't been able to fix this problem for a while now so I decided to ask here.

CodePudding user response：

when I try to run the server and client on different computers I get an error on the clients end

That is because you are using127.0.0.1 on both sides. That is the localhost loopback IP address. It works when the client and server are on the same machine, but it is not routable on the LAN network.

You need to:

change the server to listen on either 0.0.0.0 (to listen on all installed network interfaces), or its actual LAN IP address (just the network interface attached to the LAN).
change the client to connect to the server's hostname or IP address on the LAN.

I have tried changing the port multiple times but it didn't help

The problem is nit with the port, but with the IP address.