$ service nfs-kernel-server status
nfsd running

$ service rpcbind status
rpcbind start/running, process xxx

$ rpcinfo -p <hostname>

export infomation

$ showmount -e
Export list for xxxxxx:
/mnt  192.168.1.2

client information

$ showmount -a
All mount points on yyyyyy:
192.168.1.1:/mnt
192.168.1.2:/mnt

allow

$ vi /etc/hosts.allow
portmap : 192.168.1.0/255.255.255.0