Problem with recognizing and blocking IP addresses

Here’s the situation. We are seeing complaints that AVH is blocking access to site – claiming the IP address is listed in StopSpam or Project Honey Pot. The problem is – the IP address being shown as blocked is *not* the IP address being used to access the system.

For example:

Access has been blocked.

Your IP [] is registered in the Stop Forum Spam or Project Honey Pot database.

If you feel this is incorrect please contact them

Protected by: AVH First Defense Against Spam – WPMU DEV Version

If we review the IP address, it belongs to a German ISP and is indeed blocked in StopSpam.

However, the static public IPs being used to access the site are 173.67.xx.xx or (first being Verizon and the second being AT&T.)

Smartphones that received this alert were using an Easton Utilities connection who’s IP address was

None of these IP addresses have anything to do with the German IP address that was being listed as the one being blocked.

This is only one example, but exemplifies the problem. Why is this happening? What can be done to stop this?