/var/lib/nfs is the right spot. Here are my file contents:
tc@box:~$ cat /var/lib/nfs/etab
/mnt/hda2/data 192.168.0.*(rw,sync,wdelay,hide,nocrossmnt,secure,no_root_squash,no_all_squash,no_subtree_check
,secure_locks,acl,anonuid=65534,anongid=65534)
/mnt/sda1 192.168.0.*(rw,sync,wdelay,hide,nocrossmnt,secure,no_root_squash,no_all_squash,no_subtree_check,
secure_locks,acl,anonuid=65534,anongid=65534)
tc@box:~$ cat /var/lib/nfs/rmtab
192.168.0.101:/mnt/sda1:0x00000008
192.168.0.103:/mnt/sda1:0x00000002
tc@box:~$ cat /var/lib/nfs/state
tc@box:~$ cat /var/lib/nfs/xtab
/mnt/sda1 192.168.0.101(rw,sync,wdelay,hide,nocrossmnt,secure,no_root_squash,no_all_squash,
no_subtree_check,secure_locks,acl,anonuid=65534,anongid=65534)
tc@box:~$