# 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. Source: https://altcatalog.com/alternatives/portmaster/ Category: Firewall software ## Overview - **Who it's for**: 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. - **What you get**: 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. - **How it works**: 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. ## Profile - **License**: GNU General Public License v3.0 (verified 2026-07-09) - **Pricing model**: Freemium (verified 2026-07-09) - **Starts at**: €40/year (verified 2026-07-09) - **Platforms**: Windows, Linux - **Status**: active (verified 2026-07-09) ## Ranked alternatives | # | App | Alt Score | Licence | Platforms | |---|-----|-----------|---------|-----------| | 1 | [pfSense](https://altcatalog.com/alternatives/pfsense.md) | 75 | Apache-2.0 | Web | | 2 | [NetGuard](https://altcatalog.com/alternatives/netguard.md) | 70 | GPL-3.0-only | Android | | 3 | [LuLu](https://altcatalog.com/alternatives/lulu.md) | 65 | GNU General Public License v3.0 | macOS | | 4 | [Little Snitch](https://altcatalog.com/alternatives/little-snitch.md) | 60 | Proprietary | macOS | | 5 | [GlassWire](https://altcatalog.com/alternatives/glasswire.md) | 55 | Proprietary | Windows, Android | | 6 | [OPNsense](https://altcatalog.com/alternatives/opnsense.md) | 55 | BSD-2-Clause | Web | Alt Score = Verified coverage (90%) + Visibility (10%). See https://altcatalog.com/how-alt-score-works/ ## Feature comparison Legend: Yes / No / Partial / ? (not verified). | Firewall software checklist | Portmaster | pfSense | NetGuard | LuLu | Little Snitch | GlassWire | |---|---|---|---|---|---|---| | Pricing model | Freemium | OSS + paid hosting | Freemium | Donationware | One-time | Freemium | | Starts at | €40/year | $269 | Free | Free | €59 | Free | | License | GNU General Public License v3.0 | Apache-2.0 | GPL-3.0-only | GNU General Public License v3.0 | Proprietary | Proprietary | | Platforms | Windows, Linux | Web | Android | macOS | macOS | Windows, Android | | Outbound connection alerts | Yes | Partial | Yes | Yes | Yes | Yes | | Per-app rules | Yes | No | Yes | Yes | Yes | Yes | | Network-wide (router / gateway) | No | Yes | No | No | No | No | | Profiles (home, public) | No | No | No | Yes | Yes | Yes | | Open source | Yes | Yes | Yes | Yes | No | No | | One-time purchase option | No | Yes | Yes | No | Yes | No | | Traffic monitoring UI | Yes | Yes | Yes | Yes | Yes | Yes | | IDS/IPS | No | Yes | No | No | No | Partial | | Low overhead | Partial | Yes | Yes | Partial | ? | ? | ## Sources Sources for Portmaster. Each alternative is sourced on its own page. - **Platforms**: Windows, Linux — (verified 2026-07-09) - Quote: “Portmaster is a privacy suite for your Windows and Linux desktop.” - **Status**: active — (verified 2026-07-09) - Quote: “Portmaster is a free and open-source application firewall that does the heavy lifting for you.” - **License**: GNU General Public License v3.0 — (verified 2026-07-09) - Quote: “GNU GENERAL PUBLIC LICENSE Version 3, 29 June 2007” - **Pricing model**: Freemium — (verified 2026-07-09) - Quote: “Portmaster's core privacy features are free. Paid plans add investigative tools and SPN access.” - **Starts at**: €40/year — (verified 2026-07-09) - Quote: “Portmaster Plus — 40€ / Year” - **Outbound connection alerts**: Yes — (verified 2026-07-09) - Quote: “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.” - **Per-app rules**: Yes — (verified 2026-07-09) - Quote: “Cut off applications from the internet, block specific connection types, or restrict connections to certain countries per app or globally.” - **Network-wide (router / gateway)**: No — (verified 2026-07-09) - Note: Host-based application firewall on individual devices; no gateway mode. - Quote: “Portmaster is a privacy suite for your Windows and Linux desktop.” - **Profiles (home, public)**: No — (verified 2026-07-09) - Note: No network-location profiles; rules are per-app and global only. - Quote: “Rules that apply to outgoing network connections.” - **Open source**: Yes — (verified 2026-07-09) - Quote: “Portmaster is fully open source. Read the source code, audit the behaviour, or contribute.” - **One-time purchase option**: No — (verified 2026-07-09) - Note: All paid tiers are annual subscriptions; core product free. - Quote: “Portmaster Plus — 40€ / Year ... Portmaster Pro — 80€ / Year” - **Traffic monitoring UI**: Yes — (verified 2026-07-09) - Quote: “See every network connection your applications make in real time. Identify unexpected or unwanted connections and block them individually or by rule.” - **IDS/IPS**: No — (verified 2026-07-09) - Note: Malware blocking is DNS filter-list based, not behavioral IDS/IPS. - Quote: “Automatically Block Trackers & Malware ... Set Global & Per‑App Settings ... Secure DNS (Doh/DoT)” - **Low overhead**: Partial — (verified 2026-07-09) - Note: Kernel-level per-packet interception; no explicit low-overhead benchmark. - Quote: “Portmaster integrates into network stack using nfqueue on Linux and a kernel driver (WFP) on Windows. Packets are intercepted at the raw packet level” --- Ranked by verified data, never by who paid. https://altcatalog.com/trust/