Fix defaults for --sourceip and --sourceport (#45)

Use falsy values by default, otherwise the proxy thread will always attempt to bind
to 0.0.0.0:8080 which in many cases might be already in use.

Author: hrzlgnm

tcpproxy.py

@@ -44,10 +44,10 @@ def parse_args():
                         default=8080, help='port to listen on')
 
     parser.add_argument('-si', '--sourceip', dest='source_ip',
-                        default='0.0.0.0', help='IP address the other end will see')
+                        default='', help='IP address the other end will see')
 
     parser.add_argument('-sp', '--sourceport', dest='source_port', type=int,
-                        default=8080, help='source port the other end will see')
+                        default=0, help='source port the other end will see')
 
     parser.add_argument('-pi', '--proxy-ip', dest='proxy_ip', default=None,
                         help='IP address/host name of proxy')
@@ -268,7 +268,7 @@ def start_proxy_thread(local_socket, args, in_modules, out_modules):
         remote_socket.set_proxy(proxy_types[args.proxy_type], args.proxy_ip, args.proxy_port)
 
     try:
-        if args.source_ip and args.source_port:
+        if args.source_ip or args.source_port:
             remote_socket.bind((args.source_ip, args.source_port))
         remote_socket.connect((args.target_ip, args.target_port))
         vprint('Connected to %s:%d' % remote_socket.getpeername(), args.verbose)