Show remote NFS mounts on host
showmount [-ade] [host]
The showmount utility shows status information about the NFS server on the specified host. By default, it prints the names of all hosts that have NFS filesystems mounted on that host.
Because the NFS server is stateless, mount information is approximate. The showmount utility displays this information as accurately as the nfsd daemon reports it.
RFC 1094 (Appendix A: "Mount Protocol Definition")