IT operations' frameworks - Configuration Management (Puppet), Virtualization (KVM, Xen, OpenVZ, LXC, VMware), Security (OSSIM, PFSense, OSSEC, PacketFence, OpenVPN, IPSec) and Monitoring (Nagios, M/Monit, New Relic). Linux services - Apache, nginx, Postfix, Sendmail, Squid, IPTables, MySQL, PostgreSQL, Elastix, Asterisk, BIND, shell scripting (bash), kernel customization, distro customization.