A IIci should do ok.
For best performance disable all forms of in kernel compression.
( My IIci alwase seemed to fall behind if I asked it to do vj )
ie: add to your options file or /etc/ppp/peers/  file
novj
nodeflate
nobsdcomp

Your modem should have a  S register that controls
RTS-to-CTS delay - (my Zoom 56K uses S26=0).
 set it to zero to reduce overflows.
Use the modem port rather than the printer port (no fifo on the printer
port).
The real disadvantage is the limited speed of the serial port.
(57,600bps or 5.625KB/s) 

On Mon, Dec 20, 1999 9:00 AM, Jean-Francois Fortier
<mailto:jffortier@cgocable.ca> wrote:
>Hi there,
>
>        I'm looking for something to share a dial-up internet access
>between 2 others mac.  I mean a dial-on-demand router with nat. I know
>netbsd can does the job if my ISP provide me a static IP address (what I
>already have) ... I also know that 68k mac aren't good machine to do it
>because there's no DMA for the serial port (unlike powermac). I've tried
>IpNetRouter on SE30 MacOS 7.5.5 and the result were poor because of the
>hardware limitation...
>
>My question is:  Will I have exactly the same result if I try it (ppp ddr
>nat) on macbsd 68030 box.
>





  " Stamp out root login's .  .  .  . su "
    --Bruce Anderson  Computer Programming/Networking 
      Student DCTC