1. Wireshark
2. amanda.org (backup server)
3. mailarchiva.com (mail backup)
4. http://rbac.codeplex.com (remote admin for Exchange servers)
5. Core Configurator, , (DCPromo, User/Group Permission, Firewall, Screen Saver, Proxy, JoinDomain, Add/Remove Program)
6. OCS Inventory, http://launchpad.net/ocsinventory, (Inventory LAN Windows workstations and their configurations)
7. Nmap for Windows, http://nmap.org/book/inst-windows.html, (monitor host uptime)
8. Zenmap (network topology, work with nmap)
9. PowerGUI, http://powergui.org, (Powershell counterpart)
10. PAL, http://pal.codeplex.com, (Performance Analysis of Logs)
11. Systernals (Autologon, Autoruns, Pskill, Pspasswd, ADrestore)