In 2000, I was using Yellow Dog Linux on a Power Mac 7500 for this.
I even had it set up to use "dial knocking" to force it to connect remotely and send me an email with its IP address so I didn't need dynamic DNS.
In addition to NAT for my Ethernet (10BASE2) connected devices, it provided an Internet connection to my Telnet-accessible PDP-11/73 (15.2 MHz CPU, 4MB RAM, 456 MB hard drive [14" / 36 cm platters, 148 lb / 67 kg]) running 2.11BSD via SLIP.
