The best open source alternative to Portmaster is NextDNS. If that doesn't suit you, our users have ranked more than 25 alternatives to Portmaster and many of them is open source so hopefully you can find a suitable replacement. Other interesting open source alternatives to Portmaster are AdGuard, Pi-hole, simplewall and RethinkDNS.
NextDNS protects you from all kinds of security threats, blocks ads and trackers on websites and in apps and provides a safe and supervised Internet for kids — on all devices and on all networks.
Ad-blocking solution eliminating intrusive ads and preventing tracking, with malware protection. Filters pop-ups, banners, and more for clean browsing. Works in the background for ad-free surfing, protects data privacy with Spyware filter, and controls ad display in apps.
Blocks ads for all connected devices at the DNS layer without client setup. Provides web control, in-app ad and tracker blocking, DHCP and API support, regex filtering, privacy modes, audit logs, and long-term query analytics for network management.
Simple tool to configure Windows Filtering Platform (WFP) which can configure network activity on your computer.
An OpenSnitch-inspired firewall and network monitor + a pi-hole-inspired DNS over HTTPS client with blocklists.
Standalone firewall for Windows 7 and later featuring flexible rules by application, address, or protocol, wildcards, parent process filtering, SvcHost controls, blocklists, bandwidth graphs, traffic stats tracking, speed limits, and real-time network monitoring.
GNU/Linux firewall enabling interactive outbound network filtering, outbound application control, blocking of ads and malware domains, centralized GUI node management, input policy configuration, SIEM integration, real-time alerts, and user-level rule customization.
InviZible Pro uses DNSCrypt Protocol, Tor and i2pd (I2P Daemon) (PurpleI2P) to achieve maximum security, privacy and comfortable use of the Internet.
Free shared-source firewall for macOS blocking unknown outbound connections unless approved, alerts for unauthorized activity, helps detect malware, blocks OS or app data transmissions, no ads or tracking, audit-ready code on GitHub, enterprise event monitoring.
Minimal Firewall is a portable Windows firewall frontend that alerts users to internet connections without requiring custom kernel modifications or disabling core isolation, striking a balance between TinyWall's security and SimpleWall's functionality.
Gufw is an easy, intuitive way to manage your Linux firewall. It supports common tasks such as allowing or blocking pre-configured, common p2p, or individual ports port(s), and many others! Gufw is powered by Uncomplicated Firewall (ufw).
Firewalld provides a dynamically managed firewall with support for network/firewall zones that define the trust level of network connections or interfaces. It has support for IPv4, IPv6 firewall settings, ethernet bridges and IP sets.
United States
Cyprus
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Kazakhstan
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Italy
Ukraine
Spain
AdGuard is great, but it's not a firewall/port system.