server.py

# Echo server program
import socket
import ctypes

HOST = '192.168.5.102'                 # Symbolic name meaning the local host
PORT = 50007              # 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:
    c = ctypes.CDLL('C:\cddll\HDkey.dll')
    getRegNum = c.getRegNum
    data = conn.recv(1024)
    a=ctypes.create_string_buffer(data)
    getRegNum.restype=ctypes.c_char_p
    b=getRegNum(a)
    conn.send(b)
conn.close()