Develop Reference

How to protect data transmitted by socket?

This code is for sending and receiving between my PC and AWS Instance
I want to know whether the transmitted data is considered secure? or do I need something else to ensure the security of the transmitted data?
If the data is not encrypted, what is the addition to the code to make it secure?
code's client
import socket
HOST = "public ip of server"
PORT = 4444 # The port used by the server
with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
s.connect((HOST, PORT))
s.sendall(b"Hello, world")
data = s.recv(1024)
print(f"Received {data!r}")
server's code
server code
import socket
HOST = "0.0.0.0"
PORT = 4444 #open this in your router
with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
s.bind((HOST, PORT))
s.listen()
conn, addr = s.accept()
with conn:
print(f"Connected by {addr}")
while True:
data = conn.recv(1024)
if not data:
break
conn.sendall(data)

Python socket ipv6 over network not working

I am trying to connect a server to a client in python with sockets.
The problem is that with ipv6 binding, it works on my local network. What I want is to connect it to another network. These programs are written in Python 3
Here is the code of server.py:
import socket
HOST = someip
PORT = someport
server = socket.socket(socket.AF_INET6, socket.SOCK_STREAM)
server.bind((HOST, PORT))
server.listen()
Source code of client.py:
import socket
HOST = someip
PORT = someport
client = socket.socket(socket.AF_INET6, socket.SOCK_STREAM)
client.connect((HOST, PORT))
I think it is a port forwarding problem.
I know the code does nothing right now, but I want to first establish the connection.

When the server receives a request, we need to put it in a loop to accept it.
Like this
import socket
HOST = someip
PORT = someport
server = socket.socket(socket.AF_INET6, socket.SOCK_STREAM)
server.bind((HOST, PORT))
server.listen()
while True:
try:
conn, addr = server.accept()
print(f"New request from {addr}")
except KeyboardInterrupt:
server.close()

ConnectionRefusedError when trying to host python socket server on raspberry pi

I'm trying to make a basic python networking program. All I'm trying to do is send strings of text back and forth between the server and the client. I'm trying to host the server on my Raspberry Pi, and connect with a client on Windows 10. The program works great locally on my computer, but when I try to connect to my server, it gives me ConnectionRefusedError: [WinError 10061] No connection could be made because the target machine actively refused it. My server code is as follows:
import socket # Import socket module
import netifaces as ni
s = socket.socket() # Create a socket object
host = socket.gethostname() # Get local machine name
port = 12345 # Reserve a port for your service.
s.bind((host, port))
#host_ip = ni.ifaddresses('wlan0')[ni.AF_INET][0]['addr']
host_ip = "bruh?"
print("Server started! \nHostname: " + host + " \nIP: " + host_ip + " \nPort: " + str(port))
s.listen() # Now wait for client connection.
while True:
c, addr = s.accept() # Establish connection with client.
print('Got connection from', addr)
output = "Welcome to the server!".encode()
c.send(output)
c.close()
Client code:
import socket
s = socket.socket()
host = 192.168.1.21
port = 12345
s.connect((host, int(port)))
noResponse = False
serverResponse = s.recv(1024).decode()
print(serverResponse)
s.close()
Does anyone know what my problem is? Thanks.

There may be a few reasons you are getting a ConnectionRefusedError, please try the following:
Check that no firewall is blocking your connection.
Double-check the server IP, if it is wrong you may get this error.
Try to use Hercules to check the connection.
Also, I would change the code as follow:
Server:
import socket
HOST = '' # localhost
PORT = # IMPORTANT !! Do not use reserved ports
with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as sock:
sock.bind((HOST, PORT))
sock.listen()
conn, addr = sock.accept()
with conn:
print('Connected by', addr)
while True:
data = conn.recv(1024)
if not data:
break
print('Data: ',data)
conn.sendall('RT')
Client:
import socket
HOST = '' # server IP address
PORT = # server port
with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as sock:
sock.connect((HOST, PORT))
sock.sendall('Hello, I am the Client')
data = sock.recv(1024)
print('Received', data)
By doing this you are using a TCP connection and you can test your code with different TCP server and client emulators.

Socket Error : No connection could be made because targeted machine actively refused it

Note : This problem has been completely solved, as was am running client.py before server.py
Just got started with socket programming, I have created the below code and expecting to print some byte message, but it isn't doing that.
I just want to make the message available for any person on any
machine. But it's refusing by the machine to do that.
Here is my code:
server.py
import socket
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
port = 12048
s.bind((socket.gethostname(), port))
s.listen()
while True:
c, addr = s.accept()
print("Got connection from", addr)
c.send(bytes("Thank you", "utf-8"))
client.py
import socket
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
port = 12048
s.connect(('192.168.0.1', port))
msg = s.recv(1024)
print(msg.decode("utf-8"))
Some images to better explain my errors:
Any help would be appreciated!!!

It looks like in the server.py script you use s.bind((socket.gethostname(), port)) where socket.gethostname() is a hostname, but in the client.py script you use s.connect(('192.168.0.1', port)) where '192.168.0.1' is the hostname you are trying to connect.
I think there you have socket.gethostname() != '192.168.0.1' and that's the problem.
Also, you can bind to all available IP addresses on the host using this solution Python socket bind to any IP?
Let's use listen_ip = socket.gethostbyname(socket.gethostname()) for connection since socket.gethostname() may return hostname instead of IP and it will not be solved by python dns resolver in local network if it was local name, not DNS.
and use it later as s.bind((listen_ip, port)) and s.connect((listen_ip, port))
After some debugging I've got a working solution for you
There are the scripts required.
server.py
import socket
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
host = socket.gethostbyname(socket.gethostname())
port = 12_048
s.bind((host, port))
s.listen()
print("Server listening # {}:{}".format(host, port))
while True:
c, addr = s.accept()
print("Got connection from", addr)
c.send(bytes("Thank you", "utf-8"))
client.py
import socket
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
host = '192.168.1.162' # The IP printed by the server must be set here
# or we can set it using env variable named SERVER_IP
if 'SERVER_IP' in os.environ:
host = os.environ['SERVER_IP']
port = 12048
print("Connecting to {}:{}".format(host, port))
s.connect((host, port))
msg = s.recv(1024)
print(msg.decode("utf-8"))

In a chat conversation we concluded that the hardcoded IP in the question is not the correct one. This solution does have the IP he needed but it will be different in each case. Remeber that server.py needs to be launched first, and when you see the printed Server listening # IP:12048, write that IP in client.py and launch it. Client does need to be launched after seeing that line even if you already know the IP, as the server needs some time to be ready and the client will crash if it tries to connect to the server while it is not ready.
server.py
import socket
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
host = socket.gethostbyname(socket.gethostname())
port = 12048
s.bind((host, port))
s.listen()
print("Server listening # {}:{}".format(host, port))
while True:
c, addr = s.accept()
print("Got connection from", addr)
c.send(bytes("Thank you", "utf-8"))
client.py
import socket
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
host = '192.168.1.162' # The IP printed by the server must be set here
port = 12048
print("Connecting to {}:{}".format(host, port))
s.connect((host, port))
msg = s.recv(1024)
print(msg.decode("utf-8"))

Sockets on Windows 7, can't connect

Trying to create my first client-server application, I came across an error. This code is exactly the same as in the documentation, but I have problems.
Server:
import socket
HOST = 'localhost'
PORT = 9090
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.bind((HOST, PORT))
s.listen(1)
conn, addr = s.accept()
print 'Connected by', addr
while True:
data = conn.recv(1024)
if not data: break
print data
conn.close()
Client:
import socket
HOST = 'localhost'
PORT = 9090
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect((HOST, PORT))
s.sendall('Hello, world')
s.close()
After execution, I don't see the message print Connected by, addr and print data in the server part.
I use Windows 7, Komodo Firewall (I tried to close the firewall, but it didn't solve the problem), Avast Antivirus, Python 2.7.
Very interesting, that there are no errors, but the output just doesn't work.
Also, my server application just freezes until the client connects to the server. Can this be solved just using threading?
Thanks in advance.

You need to accept() and print inside the loop. (or use two loops). I'm not very familiar with socket programming in Python but I'm guess it would look something like this. (completely untested!)
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.bind((HOST, PORT))
s.listen(1)
while True:
conn, addr = s.accept()
print 'Connected by', addr
while True:
data = conn.recv(1024)
if not data:
break
print data
conn.close()

+1 to Cfreak. Basically what is happening with data is that it is getting assigned an empty string which causes the loop to break. So putting the print statement in the loop fixes the problem. Assuming you need to access that data after the loop terminates try something like
data = []
while True:
datum = conn.recv(1024)
data.append(datum)
if not datum: break
print " ".join(data)
Here is the code I am running and my computer, and it works
client
import socket
HOST = 'localhost'
PORT = 9090
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect((HOST, PORT))
s.sendall('Hello, world')
s.close()
server
import socket
HOST = 'localhost'
PORT = 9090
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.bind((HOST, PORT))
s.listen(1)
conn, addr = s.accept()
print 'Connected by', addr
data = []
while True:
datum = conn.recv(1024)
data.append(datum)
if not datum: break
print " ".join(data)
conn.close()
so I don't think it is a problem with your code... if you have a machine without a firewall/antivirus on it try the program on that machine.