Blackhole Pro

Blackhole Pro is a WordPress security plugin that detects bad bots and traps them in a virtual blackhole, where they are blocked from your site. It catches bots that ignore robots.txt, which saves server resources for real visitors and good bots.

A bad bot log keeps the IP, request and user agent for every bot, with automatic Geo/IP lookups, filterable search, custom sorting and paged results. You can delete selected bots with a click, or add a bot by IP address. An email alert goes out for every blocked bot, with the IP and a full Whois lookup, and you customize the email template with shortcodes.

You set the threshold level, the warning and blocked messages, a custom redirect URL and the HTTP status codes. You can rename the hidden trigger link and exclude it from any post or page. Good bots go on a whitelist. Blackhole does not work with caching, so leave caching off on the site.