Linux ( Debian ) Sysadmin

Hi, We require a linux system admin to perform a number of operations on a debian ( 6.01 ) webserver currently running a lamp stack for wordpress. The system itself is running well but we need primarily to ensure two things, firstly that the server is secure via a properly configured firewall and then data security via daily backups ( incremental change ? ) of both the site and its mysql database with that backup ideally arriving to an offsite location. The site should be resistant to attack with a review of directoty permissions. Caution must be taken in configuring the firewall so as not to lock us out of the server as its in a colo center. ( Read of a case of an admin starting up a firewall with SSH closed) We are also interested to have a self hosted CDN set up on a subdomain for static content and have this content served from ram to reduce disk lag and increase paralell downloads. We have looked at nginx for this , your input would be welcomed. Solid track record on freelancer or other freelance site is a prerequisite.