So, I just instlled Wordfence, started a scan and went on to checking the various options the plugin has.
I believe I didn't touch anything besides enabling caching, but now I'm locked out of anyithing that requires login. Specifically, I get the following error:
"Bad Request
Your browser sent a request that this server could not understand."
Any thoughts?
Ah, I hadn't seen this post:
http://wordpress.org/support/topic/help-im-being-locked-down-by-wordfence?replies=6