The best replacement for smoothwall is ipcop.

The best alternatives to smoothwall are rated as following:
★★★★★  ipcop
★★★★★  pfsense
★★★  untangle
★★  endian
★★  monowall
★★  clearos
★  m0n0wall
★  clarkconnect
★  sonicwall
★  astaro
  clark connect
  shorewall
  pvsense
  ipfire

Your alternative for smoothwall is not listed? Suggest!
Speaking about smoothwall, one probably shouldn't forget about dansguardian.

Other search terms related to smoothwall and their ratings are:
★★★★★ dansguardian
You have in mind a companion for smoothwall and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of smoothwall in all years. Click on graph for more.
smoothwall
ipcop
pfsense