You can check the current version of apache by running
/usr/sbin/httpd -v




CustomBuild - current

If you're using custombuild (as most new boxes are), run the following
cd /usr/local/directadmin/custombuild
./build update
./build apache
./build php n
./build rewrite_confs


from：http://help.directadmin.com/item.php?id=1

http://www.wdlinux.cn/old/mod_evasive
http://ljty11.blog.163.com/blog/static/10919414120111126105539342/

http://lxy.me/the-centos-next-script-php-ddos-and-prevention.html

http://www.tianji.me/index.php/centos/114.html

http://forum.bnxb.com/read.php?tid=183