Installation and maintenance of the following:

Configuration and maintenance of the following:

APF Firewall
System Integrity Monitor
Brute Force Detection
Linux Socket Monitor
Linux Environment Security
Process Resource Monitor
Chkrootkit
Rkhunter
Tripwire
PortMon
logwatch
iptraf
iftop
Nagios server monitoring
Cacti network monitoring
QoS (Quality of Service)
smartd (Hard Drive Checking)
tcpdump
snort
Mailmon - Sendmail monitor
Spamassassin
and more...

Enforce no-executable/no-suid operations on /tmp & /var/tmp
Enforce no-executable/no-suid operations on shared memory tmpfs
mod_dosevasive installation with custom settings
mod_security installation with custom directive settings and snort-based filter-rules
Common Security Permissions
Official System Software Updates
Increased System Logging
Backdoor Inspection
WhoCompiled - Check for compiler usage
Update Apache

clamav
disable php functions (phpinfo, system, include, chown, chmod, exec, mail, passthru, etc...)
Root Access Notification
Disable Telnet and other insecure services
Force the use of SSH protocol 2
Mask apache server & services version numbers
Set an SSH Legal Message
Daily server maintenance, adding users, compiling software, etc...
and more...