Nowadays, we need passwords for everything: our bank accounts, our e-mail accounts, our accounts on the various commercial sites, etc. And to manage these passwords, we need ... a password manager, if possible robust. There are several, but only one is certified by ANSSI (National Agency for Information Systems Security).
Libpcap allows the capture of network packets under linux, in particular. Winpcap is the equivalent for the Windows system. Winpcap was developed by programmers from the Polytechnic University of Turin.
For the management of computer parks, there are many solutions, more or less efficient, more or less cheap.
The solutions presented here, NAGIOS and GLPI-OCS, are very efficient... and free!
For VmWare virtual machine backups, Veeam offers a free, yet fully functional version (no limit on the number of hosts or virtual machines, or expiration date) of its powerful product for cloning, copying, exporting, and administering Virtual machines, even in stand-alone environments (ESXi, Hyper-V).