Cloud (Amazon AWS, Citrix Xen, VMware), Linux (Ubuntu, Red Hat, CentOS), SAN iSCSI Storage, devOps (Jenkins, Chef), Webservers (apache, Nginx), App Servers (Jboss, Tomcat), Databases (Mysql), Load Balancers (Nginx, F5), DNS (Bind), Mail (Postfix, Zimbra, Google Apps), Networking (Cisco, SonicWall)