Amiga 1200 is in the ballpark of Atari TT/Falcon and yes STing for IP, browsers etc. were available. But ST was same year as Amiga 1000 which also had just MC68000 without MMU, both Commodore engineers (who designed... Atari ST) and Atari engineers (who designed in HiToro Lorreline - than then became Amiga) had own external MMU.