Question About Starting 2nd Account for Res/Buff

[Pixio]

I always hear players talking about their Alts and other accounts etc. and someone was talking about having a 2nd account with a Cleric so he always has access to a Res. Is this legal? If this is legal I would like to start 2nd Account Cleric and level him to 50 for this reason alone - so I can res my main or res friends. This seems very useful but if I have 2 computers running from my house won't the IP be the same and will the GM think I am boxing? I have no interest in boxing but would like to buff or res only between accounts. Is this considered boxing? How is this done legally please.