what kind of code google use for detecting real ip while I'm using putty as a sock proxy?

for some reasons I'm using putty as a socks proxy and in 99% of sites my real ip will be hidden from servers but there is an interesting issue in google websites , google can't detect my real IP but 开发者_如何学编程can detect my real location. I'm wondering what kind of code google is using for detecting real location.

regards.

---

Google use the cookie to watch you regardless your IP