Advanced Policy Firewall

Advanced Policy Firewall is a free, GPL-licensed firewall for administrators protecting Internet-facing Linux servers. It suits people who need precise control of both incoming and outgoing traffic and are comfortable maintaining server-level firewall policy. Its broad rule set and IPv6 support are strong reasons to consider it, but the Linux-only scope and deliberately cautious setup require disciplined administration.

Overview

APF uses the Linux iptables/netfilter stack to combine static rules, connection-state policies, and sanity checks for attack patterns and forged source addresses. It is focused on self-hosted servers rather than desktop protection, giving administrators a framework for controlling exposed services and limiting egress.

The project is distributed under GNU GPL v2, with unrestricted use and redistribution. R-fx Networks says there are no paid tiers or enterprise editions. Support is handled through the source repository and issue tracker, while vulnerability reports are requested privately with acknowledgement within 48 hours.

Key features

Filtering works in both directions, with application and user-based outbound rules in addition to granular inbound controls. This is useful when a server must restrict which processes or accounts can reach the network, not merely which ports are open. The trade-off is administrative effort: policy design, testing and ongoing maintenance remain with the operator.

Reactive address blocking can respond to hostile sources, while GeoIP filtering and Spamhaus and DShield block lists provide additional source-screening options. These controls can reduce unwanted traffic, but they should be aligned with the services and geographies your server genuinely needs.

APF supports IPv6 dual-stack filtering and automatically creates ip6tables rules, helping keep IPv6 from becoming an unprotected parallel path. Its documentation also describes integration with BFD, cron, systemd, Docker, Kubernetes and logrotate. Fast-load snapshots are documented as loading more than 1,000 rules in under one second, a useful property for rule-heavy hosts.

Only SSH port 22 is open in the default configuration. Outbound filtering, reactive blocking and virtual network policies start disabled, so a new installation is not a finished security policy. Development mode is enabled by default and flushes the firewall every five minutes, a lockout-prevention measure during initial configuration that should be treated as temporary operating protection.

Pricing

There is no free-trial period because the complete product is free. The licence permits use and redistribution without paid upgrades, seat charges or renewal terms.

Platforms

APF runs on Linux systems with iptables/netfilter and Bash, supporting both legacy and nft iptables backends. Documented systems include RHEL, Rocky Linux and AlmaLinux 8 and 9; CentOS 6 and 7; Debian 12; and Ubuntu 12.04, 20.04 and 24.04. It is self-hosted, so deployment and compatibility depend on the server environment.

Who it's for

Choose APF when you administer Internet-facing Linux servers and need detailed ingress and egress policy, IPv6 coverage, source-blocking options and integrations with common service tooling. It is a particularly good fit for operators who can review firewall behavior and recover from configuration mistakes.

It is not the natural choice for Windows or macOS endpoints, or for users seeking a graphical, desktop-oriented security product. Teams wanting a ready-made policy with minimal server administration should look elsewhere.

Pros and cons

Pros

• Bidirectional, application-aware rules: supports granular inbound and outbound control, including user and application criteria.
• IPv6 included: automatic ip6tables rules help apply policy across both address families.
• Useful blocking sources: reactive blocking, GeoIP, Spamhaus and DShield options broaden source filtering.
• Open licensing: GPL v2 distribution has no paid tiers or redistribution restrictions.
• Server-tool integration: documented links with BFD, schedulers, containers and log rotation suit managed hosts.

Cons

• Linux and self-hosted only: excludes desktop platforms and hosted, managed deployment models.
• Important controls are off by default: outbound filtering and reactive blocking require deliberate configuration.
• Lockout risk during setup: the five-minute development-mode flush is a safeguard, not a substitute for a finished policy.
• Administrator-heavy operation: the breadth of controls brings corresponding design and maintenance responsibility.

Alternatives

BitNinja is a freemium, multi-platform option with a free VPS plan capped at two vCPUs, 2 GB RAM and 10 hosted users; choose it when those limits and broader platform access fit better than a Linux-only firewall.

ClamAV is a free GPL antivirus engine for Linux, macOS, Windows, self-hosted and API use, making it the better match for malware scanning rather than network policy enforcement.

Comodo Internet Security targets Windows with antivirus and firewall features, including a paid Pro tier; pick it for Windows endpoint protection.

Microsoft Quick Assist is a free Windows Store support utility with macOS and web support interactions, not a server firewall.

Certo AntiSpy provides freemium spyware detection and privacy tools across Android, iOS, macOS and Windows.

Dr.Web LiveDisk offers free Linux and Windows recovery from DVD or USB, while Adlice Protect focuses on Windows malware removal with free and $15-per-year plans.

Dr.Web CureIt! provides free one-time Windows scans; Malware Removal Software is a broader category starting point.

Verdict

Advanced Policy Firewall is a strong choice for Linux server administrators who need free, deeply configurable inbound and outbound controls with IPv6 and operational integrations. Choose it for policy breadth and GPL freedom; look elsewhere if you need cross-platform endpoint security, managed deployment or minimal configuration work.