HI all, newbie to learn Linux servers ( NAS, AD, etc )

Have fun.

http://rute.2038bug.com/rute.html.gz/

NAS, DNS, AD all are different technologies, which in conjugation with Unix, builds up whole IT infrastructure.

Having knowledge of these technologies would always be beneficial, because duties of a System admin varies from organization to organization. And most of the organizations expect people having versatile technical skills.

So you can start with learing basics of Linux. Find some helpful guides here.

Good luck!

In particular, I assume you mean Active Directory when you say AD. Active Directory is a Microsoft specific directory technology (though IIRC the latest SAMBA does a reasonably good job of mimicing it). Linux has its directory and authentication services such as LDAP (for a directory) and Kerberos (for single sign on) -- in fact, AD is just LDAP+Keberos combined with some custom Microsoft schemas for stuff like group policy and then wrapped up in proprietary management tools.

As for learning this stuff, you learn them the same way you learn anything else -- get a few spare boxes (or a few VMs on one reasonably modern computer) and set up file sharing (NFS or SAMBA), common authentication, Web servers, or whatever else you want to learn about. When you run into trouble, you search the Internet/dead tree books for help, asking here at LQ as a last resort if you absolutely can't figure your problem out.