If you want to REALLY get comfortable with how linux works under the hood, then Gentoo is an awesome learning tool. The amount of choices and customization options is ridiculous, from choosing which features you want to enable(compile) for an app, to choosing between bootloaders, init systems, and so on.
I haven't used Gentoo in quite a while, but I wouldn't be a professional Sysadmin today if it weren't for Gentoo.
Manche mobil Betreiber bieten auch Anrufe via WLAN an. Das wird dann abgerechnet wie als ob man in Deutschland wäre je nach Tarif.