15 essential open source tools for Windows admins

Microsoft offers great tools for enhancing your server-side experience, but open source has impressive options as well

http://www.infoworld.com/slideshow/26799/15-essential-open-source-tools-windows-admins-184364?source=more_slideshows#slide1

Essential open source Windows admin tool 

No. 1: Wireshark
No. 2: AMANDA
No. 7: OCS Inventory
No. 8: UltraDefrag
No. 10: Zenmap
No. 13: ClamWin Antivirus
No. 15: VirtualBox