0

I have a Python Socket server program, and for whatever reason the program can't bind the host and port together. Here's my code:

import socket
import sys

host = ""
port = 9999
s = socket.socket()

try:
    ("Binding socket to port: " + str(port))
    s.bind((host, 9999))
    s.listen(5)
except socket.error as msg:
    print("Socket binding error: " + str(msg) + "\n" + "Retrying...")

conn, address = s.accept()
print("Connection has been established: " + "IP " + address[0] + " Port " + str(address[1]))
while True:
    cmd = input()
    if cmd == "quit":
        conn.close()
        s.close()
        sys.exit()
    if len(str.encode(cmd)) > 0:
        conn.send(str.encode(cmd))
        client_response = str(conn.recv(1024), "utf-8")
        print(client_response, end=="")

conn.close()

I've had it print the error, and it says: Socket binding error: [Errno 10048] Only one usage of each socket address (protocol/network address/port) is normally permitted.

Does anyone know what this means and what I should do?

S.I.J
  • 979
  • 1
  • 10
  • 22
I.A.S.
  • 81
  • 2
  • 11
  • Probably an answer here: http://stackoverflow.com/questions/12362542/python-server-only-one-usage-of-each-socket-address-is-normally-permitted – Inkblot Dec 13 '15 at 15:59

3 Answers3

1

Just guessing: But did you run the code before? Because then you might not have come to perform the conn.close(). And therefore the port is still used (by your first run) when trying again. On Linux you could find the python process by calling lsof -i :9999

thgr
  • 93
  • 1
  • 8
1

Thanks guys. I figured out that I just needed to get a different port number; it is probably in use in some other program. That's a really cool suggestion about using the for loop to try to find an available port!

I.A.S.
  • 81
  • 2
  • 11
0

That error message says the port is already in use (bound). It sounds like you've got a second copy of the program running that is already bound to port 9999. Try logging out or rebooting if you can't find another way to get rid of it.

Eric Woudenberg
  • 69
  • 1
  • 3