Many times my colleagues have asked me how to change SSH port on CentOS 7, because the way they did it themselves resulted in failures of OpenSSH to start. This happened because of SELinux, and the post explains how to overcome the issue without turning SELinux off.
How to Log Successful SSH Login Attempts
Sometimes it can be useful to get notified when someone logs into the system via SSH. This article shows several possible solutions how to configure those notifications.