SPAM prevention & Secure/Hardening of my server

My server hard drive crashed, and I would like to have a aystem admin secure it, and find a solution to all spam mails. This is what my previous system admin used to perform: 1)Apache/php optimization 2)DNS optimization 3)Mysql Optimization 4)Fire wall tweaking including apf and bfd for automatically blocking Brut force attacks 5)Apache compiled with Zend optimizer and eaccelerator for increase the site performance. 6)Mod security 2 to reduce web attacks and DOS attacks 7)modevasive for preventing ddos attacks 8)Many other performance tools for monitoring 9)Updates all outdated system application binaries 10)Root scanner check for file system and application vulnerabilities. 11)Blocked all vulnerable php functions.