I just discovered something I'm not sure I like.
Whenever I post something to slashdot, slashdot connects back to port 80 on the machine I post from, looking for an open proxy on port 80.
This isn't behavior I really like to see. It's unsolicited, and more to the point, it takes advantage of a local firewall possibly being temporarily open for traffic FROM an address for a short while after connecting TO it.
There might be a "good cause", like collecting a list of open proxies for the poor guy behind the Great Firewall of China or something similar, but it's still unsolicted, clandestine and not documented.
Here are a couple of web log entries showing this:
18.104.22.168 - - [10/Sep/2008:15:47:47 -0400] "GET http://news.slashdot.org/ok.txt HTTP/1.0" 404 271 "-" "libwww-perl/5.812"
22.214.171.124 - - [10/Sep/2008:20:32:18 -0400] "GET http://mobile.slashdot.org/ok.txt HTTP/1.0" 404 273 "-" "libwww-perl/5.812"