I found if a proxy server which is in C class IP(192.0.0.1~255.255.255.255,e.g.,201.*.*.*),some website program still can display your real IP,like LEO(雷傲) or DVSBBS(动网).But if I choice a proxy server which is in A class IP(0.0.0.0~127.255.255.255,e.g.,66.*.*.*),these website will not display my real IP.
Why did this happen?I don't know.