lucy24 - 3:43 am on Aug 13, 2011 (gmt 0)
You can deny by referer (sic) but it isn't what you want here. The referer isn't the visitor itself, it's who sent them to you. That is: if you click on a link to go somewhere, the "referer" is the page where you clicked the link. You probably want the user agent.
:: shuffling papers ::
Can't imagine what's taking g### so long, but earlier today at the end of a thread* I posted an idiot-level explanation [webmasterworld.com] (sorry) of what you can expect to see in your raw logs. Almost all of that information is also available to your htaccess; you just need to find the part that is unique to the site. As wilderness said, probably a combination. Say, IP address within a certain range, and user-agent that includes certain attributes.
* Someone explained to me how to link to a specific post, but now I can't find the explanation. The long post timestamped 1:18.