I want to ask about dedicated IP, if I buy a dedicated IP for one of my domain, how bout the sub domain? Is the sub domain also use the same IP with main domain? Or do I have to buy another dedicated IP for the sub domain? Please help me, I'm confuse with my servage hosting explanation as they don't allow dedicated IP to use for both sub domain and main domain
Your host is lame. There's no technical reason why you can't use your dedicated IP for any combination of domains that you please.