In looking at my logs, I get many GET requests aimed at a directory with what appear to be auto-index parameters. Stuff like ?C=M or ?O=A. I understand those.
But I also get many requests with ?N=D, ?M=A, ?N=A, ?C=S, ?D=A. I don't have a clue what those mean. Is there some complete list of these commands that describes what they do? On my system, they just throw the requester to my index.html file. What are these requesters trying to do?
http://httpd.apache.org/docs/2.2/mod/mod_autoindex.html just gives a few of them.