The "inter" in "internet" designated a way to route among disparate networks. There were many network stacks back in the 1970s and 1980s, and even into the 199

The "inter" in "internet" designated a way to route among disparate networks. There were many network stacks back in the 1970s and 1980s, and even into the 1990s. uucp/uucpnet. Fido. DECnet. OSI. X.25. It wasn't at all clear which one would become the dominant technology, and (for a while in the early 1990s) it arguably ended up being between IP and OSI networking. Back then, path routing could be explicitly required, and you needed to know about the old SMTP % email syntax, and particularly about the routes to well-known hosts. Such as decvax. You really didn't have domains, you had bang-paths. Trivia: ftp is older than IP.