Portmap one interface

["Stuart Shillington" <stuarts46_(_at_)_mail_(_dot_)_lndn1_(_dot_)_on_(_dot_)_wave_(_dot_)_home_(_dot_)_com>]

I have two interfaces, one for the "live" connection to the internet, 
and another to the LAN. 
Is it possible for portmap and nfsd to only listen to a specific 
interface, ie. the one connected to my private LAN? 
Second, I've read the exports(5) man page, and I as I understand it, 
the following should allow only the host 192.168.1.2 to access nfs but 
I'd like to make sure...

/usr/share/mp3s -maproot=nobody 192.168.1.2

Thank you.

Stuart Shillington