Google App Engine (Python)- Strange behaviour of REMOTE_ADDR

In order to make the registration process on my website easy, I allow users to enter their email address which I will send a verification code to or alternatively they can solve a captcha.

The problem is that in order to prevent robots from registering accounts (with fake emails) I limit the number of registrations allowed per IP address and if this limit is exceeded I trigger a warning in the logs.

However ... what seems to be happening is that I am using os.environ['REMOTE_ADDR'] to check the remote address -- but it seems that I am triggering warnings on addresses that are owned by Google (66.249.65.XXX). It is possible that this is happening only after I change the version (but not confirmed). Does anyone know how/why this might be happening? Shouldn't the REMOTE_ADDR return the address of the client computer (and hopefully in all cases it would do this)?

I am curious if there is some behind the scenes re-directions going on, and if this is a normal event or if it only happens when a new version is install开发者_JS百科ed (perhaps when a new version is installed the original server then proxies the user to the new server, therefore creating the illusion that the IP address is an internal IP?)

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I believe that I have figured out the reason for seeing so many warnings from google server IP addresses. It seems that immediately after a new user registers, the google crawlers are going to the same (registration) webpage (which I send information to as a GET instead of a POST for reasons which I will not get into). Of course, since many users are registering, but there are only a few crawler computers that are checking periodic updates to my website, I am triggering warning messages that a particular (google) IP is accessing a registration area repeatedly.