AWS Python socket client TimeoutError: [WinError 10060] A connection attempt failed

I have an aws ec2 instance where I am trying to create a server to bind with my windows application the ser works but whenever I try to connect to the server from the client on my pc it gives the following error:

TimeoutError: [WinError 10060] A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond

Server.py

import socket 
import threading

HEADER = 64
PORT = 5050
SERVER = "0.0.0.0"
ADDR = (SERVER, PORT)
FORMAT = 'utf-8'
DISCONNECT_MESSAGE = "!DISCONNECT"

server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
server.bind(ADDR)

def handle_client(conn, addr):
    print(f"[NEW CONNECTION] {addr} connected.")

    connected = True
    while connected:
        msg_length = conn.recv(HEADER).decode(FORMAT)
        if msg_length:
            msg_length = int(msg_length)
            msg = conn.recv(msg_length).decode(FORMAT)
            if msg == DISCONNECT_MESSAGE:
                connected = False

            print(f"[{addr}] {msg}")
            conn.send("Msg received".encode(FORMAT))

    conn.close()
        

def start():
    server.listen()
    print(f"[LISTENING] Server is listening on {SERVER}")
    while True:
        conn, addr = server.accept()
        thread = threading.Thread(target=handle_client, args=(conn, addr))
        thread.start()
        print(f"[ACTIVE CONNECTIONS] {threading.activeCount() - 1}")


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

Client.py

import socket

HEADER = 64
PORT = 5050
FORMAT = 'utf-8'
DISCONNECT_MESSAGE = "!DISCONNECT"
SERVER = "Public IPv4 DNS"
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)
    print(client.recv(2048).decode(FORMAT))

send("hi")

The client code is running on my windows pc and the Server code is running on my aws-ec2 instance which is a Linux Os.

This is my inbound rules

I have a kaspersky firewall in my client windows but Will it effect connecting to a server?

Answer

Assuming your instance is public as I guess you can ssh into it, you need to add inbound rule to the instance’s security group which allows connections to 5050 from 0.0.0.0/0 or better, from your home/work IP address.