The author kind of mentions this but not explicitly. When you want to use obscurity always make sure it is layered on top of security. In other words, if you ar

The author kind of mentions this but not explicitly. When you want to use obscurity always make sure it is layered on top of security. In other words, if you are hiding some piece of information that you think helps in security, always make sure that it is still secure even if you do not hide it. So go ahead and obscure your SSH ports, but make sure you are using the latest version. The problem with being complacent about obscurity is that sooner than later people think that obscurity implies security and fail to ensure that their systems are secure underneath the layer of obscurity. Then the system is only secure so long as what you've obscured is obscure. That is dangerous and must be avoided.