lucy24 - 3:59 am on Jan 20, 2013 (gmt 0)
My own IP is usually in the middle of a range that I have blocked from several sites (locking myself out more than once and needing to ftp an edit) sometimes, but it jumps all over
That's where mod_rewrite steps in. (Assuming Apache here.) Most of the time a clean and simple "Deny from..." will do, but sometimes you simply have to look at more than one option: "slam the door on this IP range unless the user-agent is me".
Admittedly this is easier if you've got a browser with some distinguishing features. In other words, not Chrome ;) and definitely not a tablet.