mod_spamhaus is an Apache module for DNS Block Listing that protects web services by denying access to particular IP addresses. It can stop spam relaying via web form URL injection, and block HTTP DDoS attacks from bot-nets.
It queries sbl-xbl.spamhaus.org, taking advantage of the Spamhaus Block List (SBL) and the Exploits Block List (XBL).
1. Download the latest mod_spamhaus deb package from sid package repository (mod_spamhaus is not available for lenny but we can use the sid package)
This package is for i386. If you are using other architecture, you can find a suitable package on the bottom of this page: http://packages.debian.org/sid/libapache2-mod-spamhaus
2. Install the package
dpkg -i libapache2-mod-spamhaus_0.7-1_i386.deb
Apache is automatically restarted and the module is enabled. If you would like to test the module you can add a line to your hosts file to make it think that your IP address is blocked (pico /etc/hosts)
Replace 18.104.22.168 with your IP address and reverse it. The IP address 192.168.0.1 should read 22.214.171.124.
By default, only POST, PUT, OPTIONS, CONNECT methods are blocked. You can add GET to the list of methods blocked in /etc/apache2/mods-enabled/mod-spamhaus.conf to block the spammers from seeing your website.