I respectfully disagree; my home server is a Pentium II-233 with 256 megs of RAM, and even with 192 megs it performed acceptably. With 5.6U4, Server Manager takes about 6 seconds to load. Graphs such as those provided by the SYSMON contrib take about a second each to produce.
But a 486 with 20 megs? Yeesh, you can go to a thrift or surplus store and get a better machine than that for $20 U.S. ... surely the Netherlands isn't so computer-scarce? If you're absolutely moneyless, try a bit of trashbin diving ... you'd be surprised what large corporations throw away. For that matter, try a local computer shop ... they probably have 5 or 6 old Pentium machines running at 166 MHz they'd pay you to take off their hands. I can testify that a Pentium-166 with 128 megs of RAM makes an adequate router and/or emergency file server.
If you must, you can use that 486 with FreeSCO or Coyote Linux to make a router. Personally, I'd use it as landfill.