GlassWire is the tool people install when they want to see their network: a live graph of which application talks to which host, an alert the first time a new program goes online. Then they find that the one button they wanted — block this program — is greyed out in the free version, and the search for a free alternative begins. The free tools are strong, but none of them is GlassWire, so first decide whether you are replacing the monitor, the firewall, or both.
Versions as checked on vendor sites on 9 October 2026: GlassWire 3.11.1164, Portmaster 2.2.3, SimpleWall 3.8.7, TinyWall 3.5, Sniffnet 1.5.1, LuLu 4.5.1, OpenSnitch 1.8.0.
The short answer
For a free tool that both shows traffic per application and blocks it, Portmaster is the closest match on Windows and Linux: open source, per-application blocking, DNS filtering and a live monitor in the free version. If you only need blocking, SimpleWall (prompts, direct control of the Windows Filtering Platform) or TinyWall (no prompts, built on Windows Firewall) are free and small. If you only need to watch traffic, Sniffnet does it on Windows, macOS and Linux, and the free tier of GlassWire itself remains a good monitor. On a Mac the answer is LuLu; on Linux, OpenSnitch.
What GlassWire free actually includes
GlassWire’s pricing page draws the line clearly. The free plan gives traffic monitoring with the “network time machine” graph, first-network-activity alerts, the network scanner, per-application resource monitors and one remote connection. History is the main limit: bandwidth usage keeps one day, network history 24 hours, alert logs the current day only.
Everything under the word firewall is Premium: click-to-block, Ask to Connect, lockdown mode, profiles and bidirectional control. So are unlimited history, data export, the device list monitor and Evil Twin and ARP spoofing detection. GlassWire runs on Windows 10 or later, 64-bit and ARM64 only, plus an Android app; there is no macOS or Linux build. Premium is shareware (conditionally free).
Free GlassWire alternatives compared
| Feature | GlassWire (free) | Portmaster | SimpleWall | TinyWall | Sniffnet |
|---|---|---|---|---|---|
| Licence | Free tier; Premium is shareware | Free, open source (GPL v3); history and SPN are paid | Free, open source (GPL v3) | Free, open source (GPL v3) | Free, open source (MIT or Apache-2.0) |
| Platforms | Windows 10/11 x64 and ARM64; Android | Windows 7–11 (64-bit), Linux | Windows 7 SP1–11, x64 and ARM64 | Windows Vista and later | Windows, macOS, Linux |
| Live traffic per application | Yes, graph | Yes, connection list | Logs only | Connections list | Yes, charts |
| Block an application | No (Premium) | Yes | Yes, outbound blocked by default | Yes, blocked until allowed | No |
| Prompt on new connection | Alert only | Optional prompts | Yes | No, by design | No |
| DNS / host filtering | No | Filter lists and DNS-over-TLS | Telemetry blocklists | Blocklists | Highlights blacklisted IPs |
| History | 24 hours | Paid plans | Packet log | Current session | Current session |
Portmaster: the closest free match
Portmaster by Safing is a background service with a desktop interface that watches every connection and lets you cut an application off from the internet, globally or per app. It blocks ads, trackers and malware hosts system-wide through filter lists you can change, and routes DNS over DNS-over-TLS to a resolver of your choice. The code is on GitHub under GPL v3; the stable release is 2.2.3 from August 2026.
Mind the free/paid split. Safing’s pricing page describes the privacy features — the filter, secure DNS and the network monitor — as free, and the “investigate” features — network history and bandwidth visibility — plus the SPN (their VPN-like network) as paid. So Portmaster free is roughly GlassWire’s Premium firewall plus a live monitor, minus GlassWire’s history graph. It runs on Windows 7 through 11 (64-bit only) and on Linux with Debian/Ubuntu and Fedora packages; macOS is listed as planned. On Windows it uses a kernel driver; test it next to your VPN client first.
SimpleWall and TinyWall: free blocking, two philosophies
If the block button was the reason you looked at GlassWire, you need a free outbound firewall, not a monitor, and Windows has two good ones.
SimpleWall talks to the Windows Filtering Platform directly, blocks all outbound traffic once filtering is enabled and shows a notification the first time a blocked program tries to connect. It covers desktop programs, services, Store apps and WSL, has timed rules and telemetry blocklists, and is under 1 MB. Stable is 3.8.7; 3.9.1 adds network statistics but is still a pre-release.
TinyWall takes the opposite approach: no pop-ups by design. A new program is blocked until you allow it from a list, by clicking its window or with a hotkey. It installs no drivers or kernel components, protects Windows Firewall settings from tampering and supports UWP apps, temporary rules and boot-time filtering. Version 3.5 came out in June 2026, it is GPL v3 on GitHub, and it works on any Windows back to Vista.
Sniffnet: open-source monitoring, any desktop
Sniffnet is the usual answer to “GlassWire alternative open source” when the goal is watching rather than blocking. It is cross-platform, dual-licensed MIT or Apache-2.0, shows real-time charts and statistics, lets you inspect each connection, and can import IP blacklists to highlight suspicious hosts. Version 1.5.1 (July 2026) added connection latency. It observes only: no firewall, and data lasts for the session.
For Mac and Linux
GlassWire has never shipped for macOS or Linux. On macOS, LuLu from Objective-See is a free, open-source outbound firewall for macOS 10.15 and later: it alerts when a new outgoing connection is attempted and turns your answers into rules; current version 4.5.1. On Linux, OpenSnitch (GPL v3, 1.8.0 from December 2025) is an interactive application firewall: a daemon plus a GUI that asks about new outbound connections and keeps the rules. Portmaster also runs on Linux if you want DNS filtering too.
Two more Windows options, briefly
Comodo Firewall is free, including for business use, with application blocking and sandboxing, but its last release announcement is from December 2024 and the vendor’s requirements stop at Windows 10. NetLimiter is about per-application speed limits, and is shareware (conditionally free).
How to choose
- Monitoring plus blocking, free, on Windows or Linux. Portmaster; accept that long-term history is paid.
- Block programs and see each new connection. SimpleWall.
- Block programs and never see a prompt. TinyWall.
- Only see who uses the bandwidth. Keep GlassWire free, or Sniffnet if you also have Macs and Linux machines.
- On a Mac: LuLu. On Linux: OpenSnitch or Portmaster.
- Many PCs to manage. None of these has a central console; use Windows Firewall rules through Group Policy.
Our guide to free firewall software for Windows covers blocking; free bandwidth monitoring tools covers monitoring.
FAQ
Is GlassWire free?
There is a free tier with live traffic monitoring, alerts, the network scanner and 24 hours of history. All firewall functions and unlimited history are in Premium, which is shareware (conditionally free).
GlassWire free vs Premium — what is the real difference?
Blocking and history. Free shows what connects; Premium lets you block it and keeps usage, history and alert logs without the one-day limit.
Is there an open-source GlassWire alternative?
Yes. Portmaster (GPL v3) for monitoring plus blocking, SimpleWall and TinyWall (GPL v3) for blocking, Sniffnet (MIT or Apache-2.0) for monitoring.
GlassWire vs SimpleWall — which should I use?
GlassWire free is a monitor with no blocking; SimpleWall is a blocker with no graphs. Many admins run both: GlassWire to watch, SimpleWall to block.
GlassWire vs Portmaster?
Portmaster free blocks per application and filters DNS, which GlassWire does only in Premium. GlassWire free has the better traffic graph and 24 hours of history, which in Portmaster is a paid feature.
Is there a GlassWire alternative for Mac or Linux?
GlassWire is Windows and Android only. On macOS use LuLu; on Linux, OpenSnitch or Portmaster. Sniffnet runs on all three for monitoring.
