I don't know what you have at the moment, but I would recommend looking into the CCNA from Cisco for starting you off with networking(Doesn't cover much on security at this level. I believe one of their higher ones might). I'm doing it at the moment (actualy part of one of my A-Levels) and it seems quite for basics of networking. Although it is focused on using Cisco equipment because they run it, it does include some good overall basics. It isn't completely online, but they have Acadamies around the world. you could look and see if there is one near you here . Hope this helps.