Apache logs flooded with connections - "(via ggpht.com GoogleImageProxy)"
Solution 1:
I see traffic like this too.
- The IP addresses are always in the
66.249.64.0/19range, which is owned by Google. - The User-Agents I see are always the same one you have there.
- The URLs being requested are mostly images but sometimes not.
- Most image URLs are requested multiple times. The top two most requested images (which, incidentally, we only include in emails our platform sends) were 2/3rds of the total requests.
I'm pretty sure it's related to the recent change they made to Gmail to automatically load images in emails but to do so through a proxy so the recipient couldn't be identified.
This blog post backs me up and includes the same User-Agent.
You could probably test this by sending yourself an HTML email to your Gmail address that included a tag like this (substituting your domain in for example.com of course):
<img src="http://example.com/this_probably_doesnt_exist.jpg">
If you see the same kind of hit from this User-Agent for that URL then I am right in my guess.