In case you're looking for the current version of the mod_evasive Apache web server module, it is located here:http://www.zdziarski.com/projects/mod_evasive/
mod_dosevasive automatically responds to small to medium level abuse of a web server. Of late, we've been getting hit by some burdensome attacks so I'm in the process of fielding this on our server.
The particular machine is running an old version of Linux, Redhat 6.1 using the 2.2.19 kernel and old GCC. It looks like that version of gcc doesn't support variable argument list macros (or maybe there's some other issue that I haven't had time to track down). Anyways, the definition of the LOG() macro fails to compile. It's only used in two places in the code, so I changed it to use a fixed number of arguments and updated the calls.
Beyond that, if you're going to use it under Linux and want email notifications you need to change the call to /bin/mail. The -t option doesn't work under linux.