How to reuse the socket address python? - python-3.x

Here is server side code:
import socket
import sys
HOST = '' # Symbolic name, meaning all available interfaces
PORT = 7800 # Arbitrary non-privileged port
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
print ('Socket created')
#Bind socket to local host and port
try:
s.bind((HOST, PORT))
except socket.error as msg:
print ('Bind failed. Error Code : ' + str(msg[0]) + ' Message ' + msg[1])
sys.exit()
print 'Socket bind complete'
#Start listening on socket
s.listen(10)
print ('Socket now listening')
#now keep talking with the client
while 1:
#wait to accept a connection - blocking call
conn, addr = s.accept()
print ('Connected with ' + addr[0] + ':' + str(addr[1]))
msg = conn.recv(1024)
s.close()
whenever I use this code for the first time I can easily connect with the client and after second time I get the error "Only one usage of each socket address (protocol/network address/port) is normally permitted"
How could I modify the code that it will work again and again?

Try this line after creating s :
# ...
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
# ...
Socket options SO_REUSEADDR and SO_REUSEPORT, how do they differ? Do they mean the same across all major operating systems?

Related

How to connect a python backdoor to No-IP DNS

i'm programing a backdoor in python 3.9.1, My question is how can I connect it to my noip dns, when I use my private ip it works normally, but when I try to use the dns address it gives me an error, here is the code:
import socket
def connection():
global s
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
s.bind(('testtest123.ddns.net', 4445))
s.listen(1)
print("waiting...")
def accept_connections():
global target
target, ip_list = s.accept()
print("connection received from: " + str(ip_list[0]))
def commands():
while True:
command = input('command> ')
bit_encoded_command = str.encode(command)
if command == 'exit':
target.send(bit_encoded_command)
receive = target.recv(1024)
receive_decoded = bytes.decode(receive, "utf-8")
print(receive_decoded)
break
connection()
accept_connections()
commands()
s.close()
and the error is:
"OSError: [WinError 10049] The requested address is not valid in its context"
First of all, I recommend you not to use global variables.
As suggested by the error message, you cannot bind that address to your network interface. Use 0.0.0.0 instead and your program will handle all incoming requests.
You will then have to make sure that testtest123.ddns.net points to the machine running your code and that the port you specified is open (i.e. accessible by everyone on the Internet).
E.g.
import socket
def connection():
global s
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
s.bind(('0.0.0.0', 4445))
s.listen(1)
print("waiting...")
def accept_connections():
global target
target, ip_list = s.accept()
print("connection received from: " + str(ip_list[0]))
def commands():
while True:
command = input('command> ')
bit_encoded_command = str.encode(command)
if command == 'exit':
target.send(bit_encoded_command)
receive = target.recv(1024)
receive_decoded = bytes.decode(receive, "utf-8")
print(receive_decoded)
break
connection()
accept_connections()
commands()
s.close()

Python 3 socket client not connecting to server

I have a server.py and client.py pair. When I run the server on my machine and open multiple terminals to runs clients, I can connect fine. But when I try to run clients on another computer, the client never connects to the server. I'm pretty sure I tested this code a few months ago on multiple computers and it worked fine (though maybe I'm remembering wrong), but I think I updated my python version, so maybe that's why? How can I change my code below so it works?
server.py
import socket
from threading import Thread
import sys
clients = []
def recv(clientsocket):
while True:
msg = clientsocket.recv(1024) # wait for message from any of the clients.
print("\n" + msg.decode())
for c in clients: # send to all the clients.
c.send(msg)
def send(clientsocket):
while True:
msg = "[Server] %s" % input("\n") # wait for input
print(msg)
for c in clients: # send to all the clients.
c.send(msg.encode())
clientsocket.close()
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) # Create a socket object
host = socket.gethostname() # Get local machine name
#port = 3001 # Reserve a port for your service.
port = int(input("Enter port: "))
print ('Server started at [%s]' % socket.gethostbyname(host))
print ('Waiting for clients...')
#s.bind((host, port)) # Bind to the port
s.bind((socket.gethostbyname(host), port))
s.listen(5) # Now wait for client connection.
while True:
#Waits until someone new to accept
c, addr = s.accept()
print(addr, "connected.")
clients.append(c)
thread_recv = Thread(target=recv, args=((c,)))
thread_recv.start()
thread_send = Thread(target=send, args=((c,)))
thread_send.start()
s.close()
client.py
import socket
from threading import Thread
hostname = input("Enter hostname/IP to connect to: ")
# port = 3001
port = int(input("Enter port: "))
clientsocket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
clientsocket.connect((hostname, port))
def recv():
while True:
print("\n" + clientsocket.recv(2048).decode())
def send(username):
while True:
msg = "[%s] %s" % (username, input(""))
clientsocket.send(msg.encode()) # send message to the server.
username = input("Choose a username: ")
msg = "[%s has just connected]" % (username)
clientsocket.send(msg.encode())
thread_send = Thread(target=send, args=(username,))
thread_send.start()
thread_recv = Thread(target=recv, args=())
thread_recv.start()
while True:
# keep the threads going.
pass
Edit
Every time I start the server, it says my ip address is the same: 192.168.56.1. Even though I've turned my computer off and tried again. But when I go to Google and ask what is my ip address, it is something totally different. Why does the socket keep choosing 192.168.56.1? Is there something special about it? Is this something related to my problem?
Just bind you server to 0.0.0.0 and bind it to all network interfaces:
server.py
s.bind(('0.0.0.0', port))
Then the code in server.py will end up being something like this:
import socket
from threading import Thread
import sys
clients = []
def recv(clientsocket):
while True:
msg = clientsocket.recv(1024) # wait for message from any of the clients.
print("\n" + msg.decode())
for c in clients: # send to all the clients.
c.send(msg)
def send(clientsocket):
while True:
msg = "[Server] %s" % input("\n") # wait for input
print(msg)
for c in clients: # send to all the clients.
c.send(msg.encode())
clientsocket.close()
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) # Create a socket object
host = socket.gethostname() # Get local machine name
#port = 3001 # Reserve a port for your service.
port = int(input("Enter port: "))
print ('Server started at [%s]' % socket.gethostbyname(host))
print ('Waiting for clients...')
#s.bind((host, port)) # Bind to the port
s.bind(('0.0.0.0', port))
s.listen(5) # Now wait for client connection.
while True:
#Waits until someone new to accept
c, addr = s.accept()
print(addr, "connected.")
clients.append(c)
thread_recv = Thread(target=recv, args=((c,)))
thread_recv.start()
thread_send = Thread(target=send, args=((c,)))
thread_send.start()
s.close()

s.recv hang in python sockets

I have a client and server machine.
From client I am sending a linux command which replies after 80 sec.
As the server does not reply initial80 seconds the (s.recv) and a timeout error occurs.
Please help how to proceed here?
s= socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.settimeout(300)
s.connect((hostname, self.port))
s.sendall(self.msg)) # where msg is some linux command or script which replies after 80 seconds
#s.shutdown(socket.SHUT_WR)
while 1:
data = s.recv(1024)
if data == b"":
break
datai = datai + data.decode()
self.result[hostname.decode()] = datai
I couldn't reproduce it. Here's server and client code that is almost what you have - it works as desired:
client:
#!/usr/bin/env python3
import socket #for sockets
import sys #for exit
try:
#create an AF_INET, STREAM socket (TCP)
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
except socket.error, msg:
print 'Failed to create socket. Error code: ' + str(msg[0]) + ' , Error message : ' + msg[1]
sys.exit();
print 'Socket Created'
host = 'localhost'
port = 8888
try:
remote_ip = socket.gethostbyname( host )
except socket.gaierror:
#could not resolve
print 'Hostname could not be resolved. Exiting'
sys.exit()
print 'Ip address of ' + host + ' is ' + remote_ip
message = "The message \n"
#Code from Stackoverflow question
#s= socket.socket(socket.AF_INET, socket.SOCK_STREAM) # this is already done
s.settimeout(300)
#Connect to remote server
#s.connect((hostname, self.port)) # different variable name
s.connect((remote_ip , port))
print 'Socket Connected to ' + host + ' on ip ' + remote_ip
s.sendall(message) # where msg is some linux command or script which replies after 80 seconds
#s.shutdown(socket.SHUT_WR)
while 1:
data = s.recv(1024)
print("Ok, I get the response :)")
if data == b"":
break
datai = "DATAI: "
datai = datai + data.decode()
#self.result[hostname.decode()] = datai
print("Datai: " + str(datai))
#End
break
s.close()
server:
#!/usr/bin/env python3
'''
Simple socket server using threads.
Taken from: https://www.binarytides.com/python-socket-server-code-example/
'''
#Code for reproduce stackoverflow question
from time import sleep
#End
import socket
import sys
HOST = '' # Symbolic name, meaning all available interfaces
PORT = 8888 # Arbitrary non-privileged port
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
print 'Socket created'
#Bind socket to local host and port
try:
s.bind((HOST, PORT))
except socket.error as msg:
print 'Bind failed. Error Code : ' + str(msg[0]) + ' Message ' + msg[1]
sys.exit()
print 'Socket bind complete'
#Start listening on socket
s.listen(10)
print 'Socket now listening'
while 1:
#wait to accept a connection - blocking call
conn, addr = s.accept()
print 'Connected with ' + addr[0] + ':' + str(addr[1])
while True:
#Receiving from client
data = conn.recv(1024)
#Code for reproduce stackoverflow question
print("Waiting 80secs...")
sec = 0
while(sec < 80):
sleep(10)
sec = sec + 10
print(str(sec))
print("Ok, I'll reply...")
#End
if not data:
reply = ""
else:
reply = 'OK...' + data
conn.sendall(reply)
break
conn.close()
s.close()

Python UDP client-server with different matching incoming-outgoing ports

Based on the example at http://www.binarytides.com/programming-udp-sockets-in-python/ I modified it to run on python 3 and used two opposed ports on client and server, so replies from each one go to these ports. Here are my examples
Server:
'''
Simple udp socket server
'''
import socket
import sys
HOST = 'localhost'
PORT_IN = 8889 # Arbitrary non-privileged port
PORT_OUT = 8888
# Datagram (udp) socket
try :
s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
print('Socket created')
except socket.error as e:
print(e)
sys.exit()
# Bind socket to local host and port
try:
s.bind((HOST, PORT_IN))
except socket.error as e:
print(e)
sys.exit()
print('Socket bind complete')
#now keep talking with the client
while 1:
# receive data from client (data, addr)
d = s.recvfrom(1024)
data = d[0]
addr = d[1]
if not data:
break
reply = 'OK...' + str(data)
s.sendto(reply.encode('UTF-8'), ('localhost', PORT_OUT))
print('Message[' + addr[0] + ':' + str(addr[1]) + '] - ' + str(data).strip())
s.close()
Client:
'''
udp socket client
Silver Moon
'''
import socket #for sockets
import sys #for exit
# create dgram udp socket
try:
s1 = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
s2 = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
except socket.error:
print('Failed to create socket')
sys.exit()
host = 'localhost'
port_out = 8889
port_in = 8888
counter = 0
while(1) :
# msg = b'aoua'
msg = 'aoua' + str(counter)
try :
#Set the whole string
s1.sendto(msg.encode('UTF-8'), (host, port_out))
# receive data from client (data, addr)
s2.bind(('localhost', port_in))
d = s2.recvfrom(1472)
reply = d[0]
addr = d[1]
print('Server reply : ' + str(reply))
except socket.error as e:
print(e)
# sys.exit()
counter += 1
Problem is with the client which cannot receive any response from server and d = s2.recvfrom(1472) hangs with error [WinError 10022] An invalid argument was supplied.
I've noticed a slightly different behaviour with sock.settimeout(seconds), but I really can't figure why. Isn't d = s2.recvfrom(buffer) supposed to wait for incoming data?
What am I missing here?
Damn... Just saw it. Silly mistake. Calling s2.bind(('localhost', port_in)) in Client inside the loop.

Python socket server that can send different data to multiple clients at the same time

I'm working on a socket based application in Python 3 that will be used to configure several raspberry pi devices from a central Python server.
I have managed to write a bit of code that allows for multiple devices to connect at the same time but I can only send data from the server on the newest connection.
Here is the code:
import socket
import sys
import threading
import time
def manageClient(conn, addr):
def Ping(conn):
count = 0
while True:
conn.send(str(count).encode())
time.sleep(1)
count += 1
print(count)
conn.send(b'Welcome to the server. Type something and hit enter\n')
threading.Thread(target = Ping, args = (conn,)).start()
while True:
data = conn.recv(1024)
print(addr[0] + ': ' + data.decode())
reply = 'OK...' + data.decode()
if not data:
break
conn.sendall(reply.encode())
print('Disconnected from ' + addr[0] + ':' + str(addr[1]))
conn.close()
def addClient():
host = '192.168.1.24'
port = 8888
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
print('Socket created')
try:
s.bind((host, port))
except socket.error as msg:
print('Bind failed. Error Code : ' + str(msg[0]) + ' Message ' + msg[1])
sys.exit()
print('Socket bind complete')
s.listen(10)
print('Socket now listening')
while True:
conn, addr = s.accept()
print('Connected with ' + addr[0] + ':' + str(addr[1]))
threading.Thread(target = manageClient, args = (conn, addr,)).start()
s.close()
threading.Thread(target = addClient).start()
I would like to be able to have multiple users at the same time but a GUI that allows me to configure each device separately over the connection. I understand that this means coming up with a separate name for each connection but I'm not sure how I would achieve this. As of now bi directional communication does work even when multiple devices are connected I'm just unable to send unique messages to each system from the server once a new connection is established.
Thanks
Oliver.

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