Best Free & Open-Source LAN Screen Sharing Tools for Windows

When you need to share your computer display with colleagues in a meeting, students in a classroom, or family members across your home network, standard commercial tools like TeamViewer, Zoom, Google Meet, or AnyDesk usually come to mind.

However, all of these tools have a major limitation: they require an active internet connection and transmit your video data through external cloud servers. If your internet is down, or if you are working in an air-gapped office, laboratory, ship, or remote field site, cloud tools will not work.

Fortunately, several free and open-source software (FOSS) utilities allow you to share your screen directly over a Local Area Network (LAN) or Wi-Fi without sending a single byte to the internet.

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At a Glance: FOSS LAN Screen Sharing Comparison

Tool	License	Viewer Requirement	Direct LAN / Offline	Binary Size	Best Use Case
ScreenTask	GPL v3	Any Web Browser	Yes (Direct HTTP)	< 1 MB	Quick presentations & classroom screen sharing
Deskreen	GPL v3	Web Browser (WebRTC)	Yes	~100 MB	Secondary monitor simulation
RustDesk	AGPL v3	RustDesk Client App	Requires LAN Mode	~25 MB	Full remote desktop & mouse/keyboard control
TightVNC	GPL v2	VNC Viewer App	Yes (RFB Protocol)	~3 MB	Technical remote administration
Miracast	Proprietary	Miracast Receiver	Wi-Fi Direct only	Built into OS	Wireless TV mirroring (requires Wi-Fi Direct)

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1. ScreenTask (Most Lightweight & Browser-Based)

ScreenTask is an open-source, portable Windows utility created specifically for 100% offline, local network screen broadcasting.

Instead of requiring viewers to download companion apps, create user accounts, or install browser plugins, ScreenTask turns your PC into a miniature HTTP streaming server. Any device on your local network (laptop, iPhone, Android phone, iPad, or smart TV) can watch your display in real time simply by navigating to your local IP address in Chrome, Safari, Edge, or Firefox.

Key Highlights

• Ultra-Portable: Download size is under 1 MB (or 292 KB portable ZIP). Run it directly from a USB drive without installation.
• Zero Client Software: Viewers connect via standard HTML5 web browsers.
• True Air-Gapped Privacy: Video frames travel exclusively between devices on your local router, switch, or mobile hotspot.
• Session Security: Optional username and password protection prevents unauthorized local viewers.

Limitations

• Read-Only: ScreenTask is built for display presentation and monitoring; it does not allow remote mouse or keyboard control.

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2. Deskreen (Best for Virtual Second Screens)

Deskreen is an Electron and WebRTC-based application that turns any device with a web browser into a secondary screen for your computer.

Like ScreenTask, Deskreen delivers screen mirroring through a web browser using local Wi-Fi. It also supports virtual display adapters, allowing you to extend your desktop and drag application windows onto your tablet or phone.

Key Highlights

• WebRTC end-to-end encryption.
• Can stream either the entire screen or a single specific application window.
• Cross-platform host support (Windows, macOS, Linux).

Limitations

• Significantly heavier resource footprint due to the Electron framework (~100 MB download, higher RAM usage).
• Requires WebRTC signaling, which can occasionally struggle on strict corporate firewalls.

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3. RustDesk (Best for Full Remote Control)

RustDesk has emerged as the premier open-source alternative to TeamViewer and AnyDesk. While primarily known for internet-based remote assistance, RustDesk includes a direct IP/LAN mode that operates without public relay servers.

Key Highlights

• Full remote keyboard, mouse, and clipboard control.
• File transfer and audio support.
• Modern Rust codebase with hardware-accelerated video codecs.

Limitations

• Both the host and client computers must have the RustDesk client software installed.
• Direct LAN mode requires navigating advanced settings or configuring a local rendezvous server for seamless connection discovery.

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4. TightVNC / UltraVNC (Traditional Remote Desktop)

Virtual Network Computing (VNC) is the venerable standard for cross-platform remote desktop access using the Remote FrameBuffer (RFB) protocol. Utilities like TightVNC and UltraVNC have provided LAN-based desktop sharing for decades.

Key Highlights

• Mature, rock-solid stability.
• Extremely low overhead on legacy hardware.
• Supports both view-only and full remote control.

Limitations

• Requires every viewer to install a dedicated VNC Viewer application.
• VNC protocols lack native browser support without deploying separate WebSockets proxies (such as noVNC).
• Configuration can be intimidating for non-technical users.

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Decision Matrix: Which Tool Should You Choose?

• Choose ScreenTask if: You want to share your screen with multiple people (students, team members, meeting participants) quickly and effortlessly without making anyone install an app or create an account.
• Choose Deskreen if: You want to use an iPad or Android tablet as an extended second monitor beside your laptop.
• Choose RustDesk if: You need two-way remote control to troubleshoot someone’s PC or manage remote servers.
• Choose TightVNC if: You are managing legacy industrial equipment or Unix workstations with established VNC infrastructure.

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Getting Started with ScreenTask

If quick, browser-based offline screen sharing is what you need:

1. Download the ScreenTask Portable ZIP.
2. Extract and launch ScreenTask.exe.
3. Choose your network IP address and port from the drop-down menu.
4. Click Start Server and share the local URL (http://<your-ip>:7070) with your viewers.

For detailed setup guides, check out our Offline LAN Setup Tutorial or our Windows 11 Firewall Guide.