Yes and no. I understand what subnetmasking is. I tried to grasp the theory behind it a few months ago just because I think it's interesting to know about. But indeed, it's not very simple.

I did understand however that a lot of network admins don't understand it 100% either, and because of this use some sort of online subnet calculator to find the correct subnet and mask they need for their project. (for the record: I don't think you're one of those! )

Thanks again for the info, it should work out now!