Do Instagram allow more than one account?

I'm new to this site and new to Instagram but am learning. I've got two accounts now with around 100 followers which I intend to grow organically by following/unfollowing people who are into that niche. But I'm wondering, does IG allows people to have more than one account? I wouldnt want to spend a load of time building them up only for them to see my IP has more than one account and ban em. This is probably a very noobish question I know.

Oh and for a new account, how often is recommended to post a pic? I've been posting about 6/day. Is that too many? :S

u can do like 4-5 per i.p if its ur isp, but i would do max like 3

You can do 1-5ish per IP address. As the above poster has already said, I would not go above three accounts per IP address. You need to buy some social media proxies.

would you happen to know how many accounts would be safe to run per private proxy ?

You're allowed 5 per IP anymore you'll have to outsource.