SERVER

import socket
import threading
import sys

FLAG = False

def recv_from_client(conn):
    global FLAG
    try:
        while True:
            if FLAG:
                break
            message = conn.recv(1024).decode()
            if message == "quit":
                conn.send("quit".encode())
                conn.close()
                print("Connection Closed")
                FLAG = True
                break
            print("Client: " + message)
    except:
        conn.close()

def send_to_client(conn):
    global FLAG
    try:
        while True:
            if FLAG:
                break
            send_msg = input(" ")
            if send_msg == "quit":
                conn.send("quit".encode())
                conn.close()
                print("Connection Closed")
                FLAG = True
                break
            conn.send(send_msg.encode())
    except:
        conn.close()

def main():
    threads = []
    global FLAG
    HOST = "localhost"
    serverPort = 6500
    serverSocket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    serverSocket.bind((HOST, serverPort))
    print("Socket binded")
    serverSocket.listen(1)
    print("Listening...")
    connectionSocket, addr = serverSocket.accept()
    print("Connection Established with a client on", addr, "\n")

    t_rcv = threading.Thread(target=recv_from_client, args=(connectionSocket,))
    t_send = threading.Thread(target=send_to_client, args=(connectionSocket,))
    threads.append(t_rcv)
    threads.append(t_send)
    t_rcv.start()
    t_send.start()
    t_rcv.join()
    t_send.join()
    print("EXITING")
    serverSocket.close()
    sys.exit()

if __name__ == "__main__":
    main()


CLIENT

import socket
import threading
import sys

FLAG = False

def send_to_server(clsock):
    global FLAG
    while True:
        if FLAG:
            break
        send_msg = input("")
        clsock.sendall(send_msg.encode())

def recv_from_server(clsock):
    global FLAG
    while True:
        data = clsock.recv(1024).decode()
        if data == "quit":
            print("Closing connection")
            FLAG = True
            break
        print("Server: " + data)

def main():
    threads = []
    HOST = "localhost"
    PORT = 6500
    clientSocket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    clientSocket.connect((HOST, PORT))
    print("Client is connected to the Server\n")

    t_send = threading.Thread(target=send_to_server, args=(clientSocket,))
    t_rcv = threading.Thread(target=recv_from_server, args=(clientSocket,))
    threads.append(t_send)
    threads.append(t_rcv)
    t_send.start()
    t_rcv.start()
    t_send.join()
    t_rcv.join()
    print("EXITING")
    sys.exit()

if __name__ == "__main__":
    main()


Result: Full Duplex Communication between Server and Client has been 
 implemented successfully.