I was making routers our of old PCs (486 or early pentiums) with 2 network cards (3com or ne2000) back in 2000 with floppies and CoyoteLinux. Installed 10s of them in the students houses.
>>zoobab+(OP)
I was hoping someone would mention CoyoteLinux. It was my residential router for several years in the early 2000s. My 'disaster recovery plan' consisted of a second floppy disk (which fortunately I never had to use).