How do I configure an NFS server to accept all mount requests?
You might also try reading
man exports, which has a set of examples at the bottom from which the above is derived. You may also wish to note that
0.0.0.0/32 means "only the IP address 0.0.0.0". It is possible that you wwanted
0.0.0.0/0, which means "any IP address", instead, but
* should do as well.
You should also set permissions with the share: