The best replacement for apf is csf.

The best alternatives to apf are rated as following:
★★★★★  csf
★★★★  iptables
★★★  naf
★★  ufw
★★  shorewall
★★  cake flour
★★  bread flour
★  fail2ban
★  tpm
★  usapl
  csf firewall
  madden 08

Your alternative for apf is not listed? Suggest!
Speaking about apf, one probably shouldn't forget about fail2ban.

Other search terms related to apf and their ratings are:
★★★★★ fail2ban
You have in mind a companion for apf and it is not yet here? Propose!



Google Trends

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apf
csf
iptables