I use a floppy firewall/dhcp/router on a 486DX2/66
floppyfw
It works great, I ran NeoWatch for a month on a machine hooked to
the floppyfw but there is no need, NOTHING showed up on the
NeoWatch so I uninstalled it.
The firewall machine itself can be attacked but not
much can be done with a writeprotected floppy and
16 meg memory ramdisk, I turn it of every night
so if anything it will be gone.