This highly technical course focuses on properly securing machines running the Linux operating systems. A broad range of general security techniques such as packet filtering, password policies, and file integrity checking are covered. Advanced security technologies such as Kerberos and SELinux are taught. Special attention is given to securing commonly deployed network services. At the end of the course, students have an excellent understanding of the potential security vulnerabilities -- know how to audit existing machines, and how to securely deploy new network services.