NFS4 can make good use of connection-level security.  So, we have
several ways to establish a server connection:

 * make a plain TCP connection, and authenticate within RPC

   * server can run from inetd
 
   * server can run stand-alone

 * open an SSH connection

   * run the command directly

   * or, forward a port

 * open an SSL tunnel

   * server can run from sslwrap

The nice thing about making a connection through a command is that we
can then just run the command directly for testing purposes.