Microsoft
Windows Server 2000 to 2012R2
Windows 95 to Windows 10
Internet Information Services 5+
Microsoft DNS Server
Active Directory
Microsoft SQL Server 7.0 to the latest
Microsoft Visual Studio 2010 and 2013
.NET: C#, ASPNET
Linux
Debian 6+, RedHat Enterprise (CentOS)
Ubuntu and Mint Linux for workstation
Bind & PowerDNS
MySQL, Mariadb, Postgres, and sqlite
Apache and Nginx
Plesk, cPanel, and Virtualmin
IPTables
Bash scripting
Miscellaneous
Parallels Automation, PBA and POA
Foreman/puppet automation
XenServer
VMWare ESXi, Workstation/Player
Proxmox OpenVZ and KVM
Virtuozzo for Linux
Virtuozzo for Windows
Coding
C Sharp, ASP.NET
Structured Query Language (SQL)
HTML5/CSS
AJAX and Jquery
Javascript
PHP
Bash