Ubuntu 12.04 cannot mount NFS directory with mount after read only cannot write problem (reprint)

Transferred from: http://blog.chinaunix.net/uid-20680966-id-3810455.html

the server is using Fedora

The NFS directory on the HELPER2416 board was previously mounted on the server to read and write .
/etc/exports on the server
/opt/target * (Rw,async,no_root_squash)

today the virtual machine installed a ubuntu12.04 64bit version, can not mount, prompted what access denied, under the/etc/exports () add insecure can be resolved
then is Mount NFS directory after read-only non-writable problem, toss half a day,
later found to require Uid,gid to be consistent with the server
then use the ID command on the server
$id
uid=501 ( Jyx) gid=500 (RDD) group =500 (RDD)

modify/etc/exports
/opt/target     * (insecure,rw,sync,all_squash,anonuid=501,anongid=500)

server
$sudo Service NFS Restart

UB is mounted on NFS and found writable.

Ubuntu 12.04 cannot mount NFS directory with mount after read-only cannot write problem (reprint)