IronVNC

A free, open-source VNC (RFB) viewer written in Rust — a lightweight alternative to RealVNC / TightVNC / UltraVNC with a clean egui interface, modern encodings, RealVNC-compatible encryption, and a built-in SFTP file browser.

Iron oxidizes into rust. 🦀

Features

• Broad server compatibility — RFB 3.3 / 3.7 / 3.8, with automatic version negotiation (never downgrades a modern server to legacy auth).
• Encodings: Raw, CopyRect, Hextile, ZRLE, Tight (JPEG/Fill/Palette/Gradient), plus the DesktopSize and Cursor pseudo-encodings.
• Authentication:
  • None
  • VNC Authentication (DES challenge/response)
  • RA2 / RSA-AES (types 5, 6, 129, 130) — connects to modern RealVNC servers, including AES‑256, with full-session or handshake-only encryption.
• Session manager — saved connections with credentials; single click opens each in its own window. Connections auto-save on connect.
• MobaXterm-style SFTP panel — browse the remote host over SSH, drag-and-drop to upload, download with a click. Runs alongside the VNC session, independent of the VNC vendor.
• Quality-of-life: smooth scale-to-fit rendering, clipboard sync (both directions), scroll-wheel support, a Ctrl+Alt+Del button, desktop-name window titles, and partial-framebuffer updates for responsiveness at 4K.

Install / Build

Requires a Rust toolchain.

git clone https://github.com/hkder/ironvnc
cd ironvnc
cargo build --release
# binary at target/release/ironvnc

Usage

Launch with no arguments for the session manager:

ironvnc

Or connect directly:

ironvnc --host 192.168.1.50            # defaults to port 5900
ironvnc --host 192.168.1.50 --port 5901
ironvnc --session "My Desktop"          # open a saved session by name

If the server requires a password, IronVNC prompts for it in a popup and (on success) saves the session so you don't have to re-enter it. Saved sessions live in sessions.json next to the executable — the path is shown at the bottom of the session manager.

Headless self-test

ironvnc --test -H <host> -P <password>            # connect, verify a framebuffer decodes, exit
ironvnc --sftp-test -H <host> --user <u> -P <pw>  # verify SSH/SFTP connectivity

Security notes

• sessions.json stores passwords in plaintext and is gitignored — do not commit it.
• The RA2 host key is currently accepted without pinning (convenient for trusted networks); certificate/known-hosts verification is a planned improvement.
• VeNCrypt (TLS) and Apple ARD authentication are not yet implemented.

License

Licensed under either of Apache License, Version 2.0 or MIT license at your option.

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.