+ * If the `local_ip' is provided then this will try to bind the
+ * listener for key exchange protocol to that IP. If `local_port' is
+ * non-zero that port is used. If `local_ip' is NULL then this will
+ * automatically attempt to bind it to local IP address of the machine.
+ * If that fails then this does not bind to any address and port, and
+ * assume that the remote client will provide the listener for the
+ * key exchange protocol.
+ *