Some visitor's IPs are LOCAL instead of external

PIWIK 2.3.0.
Monitored site that has issue and piwik installation are located at different domains.

Some visitors have their local IP addresses, instead of external ones as it must be.
For example: I saw 192.168.0.24, 192.168.0.69, 10.20.24.2. This occurs for about 5% visitors.
There are normal external IPs for those visitors in Apache logs.
My hosting is not behind proxy server.

Maybe you are using a proxy? How do I configure Piwik when the server is installed behind a proxy?

Hi, Matt
No, my web server is not behind proxy. And I wrote: the most IP addresses are detected in right way. The problem is for a few IP’s in a day.

I don’t know what could cause this… Could they be users on your intranet / local network ?

NO. Those are not my users indeed. They are surely from different common EXTERNAL networks. And what’s more - there are normal external IPs of those visitors in Apache logs. But PIWIK can’t see it.

Piwik should not do anything special so I think this may be a misconfiguration somewhere in the server or network ?

11 months ago I reported about this problem? but nothing has changed.
Sometimes Piwik shows IP as LOCAL one.
Please see attachments - piwik’s visitor log screenshot and Apache log for visitor, that is not defined by Piwik.
[attachment 2304 piwik_problem.jpg]
[attachment 2303 apache_log_fragment.png]