From LQWiki

NFS is Sun Microsystems' Network File System. It was the industry standard in networked file-systems for a time, and is still in use. Linux systems can export directories via an NFS server, or mount directories exported by other NFS servers. nfs is as easy to use as to abuse; it lacks almost all modern security features. For most uses it is far more advisable to use samba instead.

Your NFS shares are configured in /etc/exports. To see all NFS exports of a server localhost, use

showmount -e localhost

See also

nfsd - how to set up an NFS server