This course explores Unix, Unix-like OSs, firewalls, and VPNs. Introducing students to the basic concepts of Unix/Linux, different file systems, editors, differences between Linux distributions, creating users, permissions, package managers, man pages, and other places to find help. This course also explores network security basics, including how hackers access online networks and the use of Firewalls and VPNs to provide security countermeasures. Students focus on both managerial and technical aspects of security. Coverage includes packet filtering, authentication, proxy servers, encryption, bastion hosts, virtual private networks (VPNs), log file maintenance, and intrusion detection systems.