an be specified as a standard IP address or as a hostname. Note that when no SPA address is specified, the Aldaba client will try to determine one. By default it picks the assigned IP address of one of the network interfaces present in the local system. If you are behind a NAT device, you'll need to set up the NAT's public IP address in order to access the knock port. Check option --resolve for information on how to determine that address automatically.
</DL>

<P>

<B>-S </B><B></B><I>address</I>, <B>--bind