NFS Setup
Edit the /etc/exports file (which won't exist, you'll have to create a new file) and add the following:

/usr/nfsroot -maproot=0

The IP address used here is the IP address of the client computer, not the NFS Root server.

Edit the /etc/rc.conf once again, and add the following:

nfs_server_flags="-u -t -n 4"

Start the NFS server by typing the following:

/etc/rc.d/nfsd stop
/etc/rc.d/mountd forcestop
/etc/rc.d/rpcbind forcestop
/etc/rc.d/nfsd start