Fail2ban Centos 5

http://www.md3v.com/install-fail2ban-on-centos-5-5

How to enable the half-open TCP connections limit Windows 2008 SP2

http://support.microsoft.com/kb/969710/he

Network scanner

http://www.softperfect.com/products/networkscanner/

DNS

https://www.omerta.cc/showthread.php?t=8089

Nessus on BT5

http://pauldotcom.com/2011/05/activating-nessus-on-backtrack.html

Snort on CentOS 6.2

http://nachum234.no-ip.org/security/snort/001-snort-installation-on-centos-6-2/

IPTables

http://wiki.centos.org/HowTos/Network/IPTables

LAMP on CentOS 6.2

http://www.howtoforge.com/installing-apache2-with-php5-and-mysql-support-on-centos-6.2-lamp

LAMP

http://www.lamphowto.com/

20 Linux System Monitoring Tools Every SysAdmin Should Know

http://www.cyberciti.biz/tips/top-linux-monitoring-tools.html