Quoting Frank van der Linden,

> 	a) Decoupling the mount/unmount requests from the later NFS operations
> 	   again, and reinstating the '-n' flag to the mountd? This would
> 	   have the rather strange effect that you can configure your system
> 	   to allow mounts from non-reserved ports, but that subsequent
> 	   operations will fail anyway because they come from non-reserved
> 	   ports.

> 	b) Adding a new option to the mountd which says "Always require
> 	   reserved ports for mount requests, regardless of the usage of
> 	   -noresport".

Replying to myself here, I should add a 3rd option:

	c) Having another option besides '-noresport' in the exports file,
	   which controls the mount protocol. So you will have -noresport
	   control the NFS RPC requests, and something else, say
	   -noresmnt, control the mount RPC requests. This is perhaps
	   the most flexible way, as it allows you to control everything
	   in one place, and per filesystem/host combination.

- Frank