the typical question (how can my brother and I share the same IP)

Hi, I expect that this question has been asked many times before, but I'm still confused and afraid of getting banned. my brother wants to create an account, but off curse we are going to share the same IP. what can we do?
is it allowed to 2 accounts to share the same IP ?
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EDIT: sorry I found the answer in the FAQ. we can play from different computers while using the same IP. sorry I couldn't delete the thread later.