Zyxel NAS540 NFS exports all shares RW world by default ?

While poking around with nfs exports on my zyxel nas 540 I noticed that, it is useless to set any DN/IP filter since the whole nfs directory is exported world wide RW as:

/i-data/<disk id>/nfs *(rw,sync,crossmnt,fsid=0,no_subtree_check,wdelay,no_root_squash) #

This share is not visible from the web interface but can easily be confirmed using showmount on any other system on the network:

showmount -e nas_ip

Export list for nas_ip:

/i-data/<disk id>/nfs               *
/i-data/<disk id>/nfs/kitties

So you better comment out /i-data/<disk id>/nfs * line in /etc/exports and then run:

/i-data/sysvol/.PKG/NFS/bin/exportfs -r

You get what you pay for I guess.