Portmaster review
A focused Windows and Linux firewall with detailed application and outbound controls.
Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026
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.
Portmaster pros and cons
- 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
Portmaster fact sheet, pricing and score →
Advertiser disclosure: iTechGuides is reader-supported. Vendors can pay for top positions in our rankings and for a place on other products' pages, and we may earn a commission when you click some links. Bought places stand at the number bought; this page and our disclosure say so. Paying vendors may get a fuller, more detailed review from our editors, and that review can change their score. How we rank.
Last updated · How we research and update