Portmaster

At a glance

• Editor score
  6.1 / 10
• Pricing
  Free plan
• Best for
  Desktop application firewall users
• Free plan
  Yes
• Paid from
  €40/yr
• Outbound control
  Advanced
• Facts checked
  22 Sep 2026

• Where it wins

  • Free plan includes per-application rules, monitoring, and Secure DNS
  • Controls inbound and outbound traffic by domain, IP, port, and protocol
  • Open-source Windows and Linux application firewall with malware blocking

• Where it doesn't

  • Coverage is limited to Windows and Linux
  • Investigative features and SPN access require a paid plan
  • Paid plans add cost for users needing priority support or multiple devices

Our verdict on Portmaster

Portmaster is an open-source application firewall for Windows and Linux, designed for people who want detailed control over application network connections. It combines real-time monitoring with per-application and global firewall settings, inbound connection blocking, outbound rules, tracker and advertisement filtering, malware-host blocking, and DNS-over-TLS. Its audience is desktop users who want privacy controls alongside traditional firewall rules rather than a firewall focused only on basic inbound protection.

The free plan provides a substantial core: a privacy filter, Secure DNS, a network monitor, and per-application firewall rules. Users can match outbound traffic by domains, IP addresses, countries, protocols, and ports, while connection prompts and desktop notifications provide visibility when applications communicate. Paid plans add privacy and investigative features, priority support, and use on up to five devices. Portmaster Plus costs €40 per year, while Portmaster Pro costs €8 per month or €80 per year; Pro also includes SPN access. The plan structure suits users who can stay with the free controls as well as those who want broader privacy tooling.

Portmaster’s standout strength is the breadth of its traffic controls within a desktop application firewall. It covers both inbound and outbound rules and adds system-wide blocking for trackers, advertisements, and malware hosts. DNS-over-TLS supports configurable providers, and SPN routing can be configured with exclusions on the Pro plan. The main fit question is platform coverage: the published product details focus on Windows and Linux, with macOS and mobile support described as planned. Choose Portmaster if application-level visibility, open-source software, and granular network rules matter; choose another option if you need a firewall for macOS or mobile devices today.

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Portmaster pricing

All 3 Portmaster plans and prices →

Portmaster fact sheet

Alternatives to Portmaster

• FortiGateA broad hybrid firewall platform for organizations that need deep security and network controls.9.4
• Arista NG FirewallA broad firewall platform with a free plan and extensive network controls.9.3
• Google Cloud NGFWGoogle Cloud-native firewall protection with free rule evaluation and usage-priced advanced controls.9.2

See all Portmaster alternatives →

Featured on iTechGuides

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Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026

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Last updated 7 Oct 2026 · How we research and update