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Installing mod_evasive on cPanel and/or Apache

This guide details how to install mod_evasive on cPanel to help protect against DDOS attacks, brute force attacks  and other irritants.

It uses an internal hash table of IPs and URLs and can temporarily block web requests to anyone requesting a large number of page views, or making many concurrent requests. Properly configured it can help evade DDOS attacks and keep your customers happy.

You can integrate it with iptables and hardware firewalls too if you like.

This guide is only cPanel specific to the point where you edit the configuration file.

Check the latest version from the mod_evasive web site. It is 1.10.1 in Jan 2010.

wget http://www.zdziarski.com/projects/mod_evasive/mod_evasive_1.10.1.tar.gz
tar zxvf mod_evasive_1.10.1.tar.gz
cd mod_evasive

I am assuming you use apxs to load dymanic modules into apache. You really should.

/usr/local/apache/bin/apxs -i -a -c mod_evasive20.c

cPanel users only, we need to distill the apxs module into Apache so it isn't lost next time you rebuild or upgrade cPanel/Apache.

/usr/local/cpanel/bin/apache_conf_distiller –update

cPanel users can edit /usr/local/apache/conf/includes/post_virtualhost_2.conf or use the Apache Configuration option in WHM.

Vanilla Apache users can just stick the config in their httpd.conf.

<IfModule mod_evasive20.c>
DOSHashTableSize    3097
DOSPageCount        2
DOSSiteCount        50
DOSPageInterval     1
DOSSiteInterval     1
DOSBlockingPeriod   3600
</IfModule>

Optionally you can also add the following directives;

DOSEmailNotify      you@yourdomain.com
DOSSystemCommand    "/etc/apf/apf -d %s'"
DOSLogDir           "/var/lock/mod_evasive"

I use APF firewall, with the DOSSystemCommand so I can automatically dop offending IPs at the firewall rather than at Apache.

Hopefully you will never see an email from mod_evasive, but you know its there, ready and waiting.

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