When looking at my Apache2 access logs, I occasionally see GET requests asking my server for a page on a completely different server. For example:
xx.xx.xx.xx - - [18/Jan/2012:07:12:10 -0500] "GET http://someotherserver.com/?sometimesmorestuff=likethis HTTP/1.1" 200 389 "-" "Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:18.104.22.168) Gecko/20080201 Firefox/22.214.171.124"
I remembered reading something about that in the past, but at the time I had never seen that on my server, so I didn't worry about it.
Now that I am seeing it on my server, I just ran a test and it appears that my site does indeed serve requests for content from other servers. This seems like a bad thing. So, two questions:
A) Is this something I should be worrying about?
B) How can I fix it?
I've tried a little Googling, but I don't even know what this sort of thing is called, and that makes it difficult.