Aggressive anti-spam plugin that eliminates comment spam, trackback spam, contact form spam and registration spam. Protects against malicious attacks.
2/21/2015: I found that I cannot handle support other than try to fix problems when pointed out. If you are locked out of your website, delete the plugin and don't use it again. If you find it is too aggressive then start un-checking boxes in the configuration until it works. My sites are hosted on SiteGround.com. I pay for this service, and the plugin works perfectly. I can recommend http://www.SiteGround.com wholeheartedly. If you self-host or you are on a free or cheap hosting company that uses a proxy server or does not implement basic PHP functions then you cannot use this plugin.