GlassWire

WatchGuard Firebox

WatchGuard Firebox is a line of next-generation firewall (NGFW) products spanning physical appliances, virtual instances, and cloud deployments. The lineup includes tabletop T Series appliances for small businesses and rackmount M Series appliances for enterprises, plus FireboxV for virtualized environments and Firebox Cloud built specifically for AWS and Azure. Its Unified Threat Management services bundle AI-powered antivirus and advanced threat protection with sandboxing. Firebox also provides enterprise-grade VPN for secure remote access and, through FireCloud Gateway integration, zero trust access so remote users and private applications can be reached securely through the same appliance. WatchGuard positions Firebox for small and medium businesses, distributed enterprises with multiple locations, and organizations needing cloud infrastructure security, with flexible modular licensing and pricing available directly from the company.

ZoneAlarm

ZoneAlarm is a long-running personal security brand now owned by Check Point Software Technologies, built around a two-way firewall that inspects both inbound and outbound traffic. It pairs that firewall with real-time antivirus and anti-spyware scanning, anti-phishing protection, and threat emulation aimed at catching zero-day threats before they execute. The product line ranges from a free firewall and free antivirus up through paid tiers like ZoneAlarm Pro Antivirus + Firewall and ZoneAlarm Extreme Security NextGen, which adds ransomware protection and broader coverage. Apps are available for Windows, Mac, Android, and iOS, and the suite has picked up awards such as PCMag Editors' Choice and AV-Test certifications over the years.

Portmaster

Portmaster, made by the Austria-based company Safing, is a free and open-source application firewall for Windows and Linux that gives users visibility into every network connection made by every application on their computer. Rather than just blocking traffic at the network edge, it lets users set per-application rules to allow, block, or restrict specific programs, and can completely isolate an app from the internet if desired. Beyond application-level control, Portmaster blocks ads and trackers system-wide at the DNS level, meaning the protection applies across all applications rather than just a browser. It supports restricting connections by country and blocking specific domains directly. Safing also offers SPN, a separate paid privacy network product, and a Pro tier for Portmaster itself, alongside the free core firewall application.

NetLimiter

NetLimiter is a Windows utility for controlling and monitoring network traffic on a per-application basis, letting users set maximum upload/download speeds for individual apps, the whole system, specific users, or individual connections. It shows real-time traffic with live visualization and keeps long-term local statistics for historical analysis. Interactive rules can block selected applications from reaching the internet based on conditions like application path, domain, IP range or user account, and data quotas can automatically throttle or block traffic once a transfer limit is hit. It is sold under Locktime Software as a Pro edition with time-limited licenses covering one or two-year usage periods.