Last week was my third and final part of my series that introduced SELinux on Techrepublic: Practical SELinux: Port contexts and handling access alerts. This one finishes off what we were looking at in part two, and introduces port contexts (ensuring that a program can only listen to specified ports and nothing else), and shows us how to use sealert to look at violations that SELinux is reporting and how we can fix them, or at least make the system understand that certain behaviour is both desirable and permissible. It also looks at SELinux booleans and how to toggle certain functionality with the getsebool and setsebool command.