[root@mail ~]# umount /mnt/gjp
[root@mail ~]# mount
/dev/sda2 on / type ext3 (rw)
proc on /proc type proc (rw)
sysfs on /sys type sysfs (rw)
devpts on /dev/pts type devpts (rw,gid=5,mode=620)
/dev/sda1 on /boot type ext3 (rw)
tmpfs on /dev/shm type tmpfs (rw)
none on /proc/sys/fs/binfmt_misc type binfmt_misc (rw)
sunrpc on /var/lib/nfs/rpc_pipefs type rpc_pipefs (rw)
192.168.10.99:/public on /mnt/nfs type nfs (ro,soft,intr,addr=192.168.10.99)
[root@mail ~]# mount 192.168.10.99:/gjp /mnt/gjp
[root@mail ~]# cd /mnt/gjp
[root@mail gjp]# ll
total 0
-rw-r--r-- 1 nfsnobody nfsnobody 0 Oct 15 2012 gjp
[root@mail gjp]# touch guolu
[root@mail gjp]# ll
total 0
-rw-r--r-- 1 nfsnobody nfsnobody 0 Oct 15 2012 gjp
-rw-r--r-- 1 root root 0 Oct 15 2012 guolu
取消映射后:发现root用户，更不安全！还是用映射的好！