Can't record 'location_ip' right

Hello,everyone.I’ve been using Piwik for a couple of days, it’s an excellent software and a great help to my Summer Intern.
But I discover that my Piwik can’t record the right ‘location_ip’ in table ‘piwik_log_visit’.In my mysql,there are ony three values for this property:
and only the second and the third one seems valid.
But among 1026 records in mysql, 1018 are the first one( invalid).
I think its must be wrong somewhere,who can help me figure out where the problem is?
thank you! is a reserved netblock. This is probably the address of your reverse proxy. Please contact your sysadmin about how it is translating remote IP addresses. The defacto standard is to pass along the remote ip address in HTTP_X_FORWARDED_FOR or HTTP_CLIENT_IP.

thanks very much.I’ll try the method you told me!