If you're a programmer I recommend you (try to) create your own console like Webmin. I learned everything I've ever needed to know about various mail servers,

If you're a programmer I recommend you (try to) create your own console like Webmin. I learned everything I've ever needed to know about various mail servers, web servers, databases, various configuration files and system level stuff. You don't have to use it or go very far with the actual project in terms of polishing, but it makes for an excellent educational project.