Security incidents are rising at an alarming rate every year. As the complexity of the threats increases, so do the security measures required to protect networks. Data center operators, network administrators, and other data center professionals need to comprehend the basics of security in order to safely deploy and manage networks today. This paper covers the fundamentals of secure networking systems, including firewalls, network topology and secure protocols. Best practices are also given that introduce the reader to some of the more critical aspects of securing a network.