AIX

chnfsdom #return correct domain
chnfs  -r /export
chnfs  -p /export
configured and shared pseudo root

#etc/exports
/export -nfsroot
/var/pubblica -exname=/export/pubblica,vers=4,sec=sys:krb5p:krb5i:krb5:dh,rw

exportfs -a

mount
ibmunix  /pubblica        /mnt2            nfs4   Oct 23 00:57 vers=4,sec=sys

share
/var/pubblica -exname=/export/pubblica,vers=4,sec=sys:krb5p:krb5i:krb5:dh,rw

showmount -e
no exported file systems for ibmunix

man showmount

       Note: The showmount command returns information maintained by the mountd daemon. Because NFS Version 4 does not use the
       mountd daemon, showmount will not return information about version 4 mounts.