Opening socket to outside computer with Python

Question

I am using the following code to open a socket on my computer. When I go to my_ip:5000 on my computer the program responds. However, when I use another computer, nothing happens.

HOST = 'my_ip'                 # Symbolic name meaning the local host
PORT = 8000              # Arbitrary non-privileged port
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 1:
    data = conn.recv(1024)
    if not data: break
    conn.send(data)
conn.close()

I'm not sure if this is an issue with the firewall or not. When I start up the test server in django using manage.py runserver my_ip:8000 I am able to connect to the machine from a different computer. I'm not sure what is causing me not to be able to connect from another computer using the code above...

Answer 1

By setting HOST to 'my_ip', you may listen to a private IP that only resolves to your computer for your computer. The best-known example is 127.0.0.1. Instead, pass an empty string (HOST='') to listen to any requests coming in at the specified port. Make sure to use the same port number, i.e. either 5000 or 8000, on both machines.

Also, check whether a firewall between the computers (or installed on one of them) prevents the connection.

To test whether your computer is reachable in principle, run python -m SimpleHTTPServer in a directory without private information on the server and try to reach the webserver started with that from the client.