Alternatives to Portmaster
Open source app firewall with DNS filtering
Portmaster ranks #5 of 7 in Firewall software, with an Alt Score of 55. It is licensed under GNU General Public License v3.0, freemium from €40/year and available on Windows and Linux. 9 of 9 checklist rows are verified against a public source.
Privacy-conscious Windows and Linux users who want to see and control exactly what their applications are doing on the network, rather than relying on cloud-based or subscription VPN-style tools.
Portmaster is a free, open-source application firewall that shows real-time network connections per application and lets you block or allow them individually. It includes a secure DNS resolver with system-wide tracker and ad blocking, plus rules for restricting apps by connection type, domain, or geographic destination. All configuration is local, with no account or cloud dependency required.
A background core service integrates with the OS network stack to intercept and identify connections as they happen, then applies your per-app and global rules along with its DNS-based privacy filter before allowing or blocking traffic. A desktop UI provides visibility into this activity and lets you adjust rules live.
Why people leave Portmaster
Dashed reasons are sourced facts; the rest are opinions. Vendors can dispute.
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Ranked alternatives
Ordered by Alt Score. Click any score to see the breakdown.
Feature comparison
Rows come from the Firewall software checklist (13 rows). Human-verified cells only. ? means the value has not been verified.
| Firewall software checklist | Portmaster | pfSense | NetGuard | LuLu | Little Snitch | GlassWire |
|---|---|---|---|---|---|---|
| Pricing model | ||||||
| Starts at | ||||||
| License | ||||||
| Platforms | ||||||
| Outbound connection alerts | ||||||
| Per-app rules | ||||||
| Network-wide (router / gateway) | ||||||
| Profiles (home, public) | ||||||
| Open source | ||||||
| One-time purchase option | ||||||
| Traffic monitoring UI | ||||||
| IDS/IPS | ||||||
| Low overhead |
Every fact and feature listed for Portmaster is verified against its own pages. Each alternative is sourced on its own page.
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Platforms Windows, Linux verified 2026-07-09
Portmaster is a privacy suite for your Windows and Linux desktop.
https://github.com/safing/portmaster -
Status active verified 2026-07-09
Portmaster is a free and open-source application firewall that does the heavy lifting for you.
https://github.com/safing/portmaster -
License GNU General Public License v3.0 verified 2026-07-09
GNU GENERAL PUBLIC LICENSE Version 3, 29 June 2007
https://raw.githubusercontent.com/safing/portmaster/main/LICENSE -
Pricing model Freemium verified 2026-07-09
Portmaster's core privacy features are free. Paid plans add investigative tools and SPN access.
https://safing.io/pricing/ -
Starts at €40/year verified 2026-07-09
Portmaster Plus — 40€ / Year
https://safing.io/pricing/ -
Outbound connection alerts Yes verified 2026-07-09
If set to 'Prompt', the Portmaster will prompt you in the User Interface as well as via Desktop Notifications (if enabled) to make a decision about a connection.
https://docs.safing.io/portmaster/settings -
Per-app rules Yes verified 2026-07-09
Cut off applications from the internet, block specific connection types, or restrict connections to certain countries per app or globally.
https://safing.io/features/ -
Network-wide (router / gateway) No verified 2026-07-09
Host-based application firewall on individual devices; no gateway mode.
Portmaster is a privacy suite for your Windows and Linux desktop.
https://github.com/safing/portmaster -
Profiles (home, public) No verified 2026-07-09
No network-location profiles; rules are per-app and global only.
Rules that apply to outgoing network connections.
https://docs.safing.io/portmaster/settings -
Open source Yes verified 2026-07-09
Portmaster is fully open source. Read the source code, audit the behaviour, or contribute.
https://safing.io/features/ -
One-time purchase option No verified 2026-07-09
All paid tiers are annual subscriptions; core product free.
Portmaster Plus — 40€ / Year ... Portmaster Pro — 80€ / Year
https://safing.io/pricing/ -
Traffic monitoring UI Yes verified 2026-07-09
See every network connection your applications make in real time. Identify unexpected or unwanted connections and block them individually or by rule.
https://safing.io/features/ -
IDS/IPS No verified 2026-07-09
Malware blocking is DNS filter-list based, not behavioral IDS/IPS.
Automatically Block Trackers & Malware ... Set Global & Per‑App Settings ... Secure DNS (Doh/DoT)
https://github.com/safing/portmaster -
Low overhead Partial verified 2026-07-09
Kernel-level per-packet interception; no explicit low-overhead benchmark.
Portmaster integrates into network stack using nfqueue on Linux and a kernel driver (WFP) on Windows. Packets are intercepted at the raw packet level
https://github.com/safing/portmaster
FAQ
Yes. NetGuard and GlassWire have a free tier or are fully free. Free-tier limits in the comparison table are verified and dated.
pfSense, NetGuard and LuLu — every license claim links its source.