Advanced Policy Firewall vs Microsoft Safety Scanner

Advanced Policy Firewall is a free GNU GPL firewall system for Internet-deployed Linux servers. It uses iptables/netfilter to combine static rules, stateful connection policies, and checks for attack patterns and forged source addresses. Administrators can configure granular inbound and outbound filtering, including rules based on users and applications. Additional controls include reactive address blocking, GeoIP country filtering, and Spamhaus and DShield lists. IPv6 dual-stack filtering can create ip6tables rules automatically. Documentation describes snapshots loading more than 1,000 rules in under one second, plus integrations with BFD, cron, systemd, Docker/Kubernetes, and logrotate. APF requires Linux, iptables/netfilter, and Bash, and supports legacy and nft backends. Listed systems include RHEL/Rocky/AlmaLinux 8 and 9, CentOS 6 and 7, Debian 12, and Ubuntu 12.04, 20.04, and 24.04. Development mode initially flushes the firewall every five minutes; only SSH port 22 is open by default.

Microsoft Safety Scanner has no write-up on Specifiction yet; its figures are above.