Portals

[Lavos]

What sort of magic caster is required to open portals in D&D. How far apart can the portals be? Can you make a permanent portal?

[ShadowWalker]

Wizards, and I would suggest a wizard that specializes in bouncing between planes. There are a lot of these, and back in the day, you would find them in Sigil ALL the time. Magical components have always been difficult to find, obtain and certain mages have both funded adventures, and quest; or they have tricked others into obtaining them. Sometimes it's best to find them in other planes of existence. Portals can range in size, but for the most part, you can have a room filled with portals, as long as they are not occupying the same space and time as any other portal and you should be good. Otherwise, things blow up.