Indeed. Through the 90s at $JOBS, my desktop workstation has a public IP address and was directly on the Internet without any kind of firewalling. Sendmail ran

Indeed. Through the 90s at $JOBS, my desktop workstation has a public IP address and was directly on the Internet without any kind of firewalling. Sendmail ran locally and I'd send/receive email to/from the world directly on my workstation. Same for FTP, HTTP, etc. That's how the Internet was originally intended to operate.