Control NFS exported filesystems

[CALT at SLACVM.SLAC.STANFORD.EDU]

On my machines, the 530s, there are a number of filesystems exported
to be mounted by a number of other machines here.

By exprience, I learned that mounting NFS filesystems by the
hard/foreground options may cause the machines hanging, while
by the soft/backgroud options seems to work OK.

Here comes a problem: If some machine DOES mount my exported filesystems
by the hard/foreground optins, it may cause my machines hanging. Is there
any way to configure my exporting filesystems as follows:
   Only the machines which use the soft/backgronud options will be allowed
to use my exported filesystems.

Is it possible? Or is there any other way to solve the problem?

Thanks in advanc for any advice!

Ching Shih
shih at cithex.bitnet
shih at cithe1.cithep.caltech.edu