IronRDP

A Rust implementation of the Microsoft Remote Desktop Protocol, with a focus on security.

IronRDP is a modular suite of Rust crates implementing RDP, the protocol behind Windows Remote Desktop. It is not a single monolithic client: it is a set of composable building blocks — PDU encoding/decoding, connection and session state machines, virtual channels, image codecs — that you can assemble into a client, a server, or a proxy, on native platforms, in the browser via WebAssembly, or from .NET through FFI bindings.

The core protocol crates do no I/O, are no_std-compatible, and are continuously fuzzed. You bring the transport and the runtime; IronRDP brings the protocol.

Highlights

• Sans-I/O core. Connection and session logic are state machines with no sockets, no threads, and no runtime attached. Drive them with blocking I/O, tokio, futures, or your own event loop.
• Security first. Parsing is treated as a hostile-input surface: every core crate is fuzzed, unsafe is heavily linted, and the workspace enforces a strict correctness lint policy.
• Runs everywhere. Native binaries, a WebAssembly module for browsers, and C#/.NET bindings all build from the same protocol core.
• Client and server. Use the connector to talk to a Windows host, or the acceptor and server skeleton to expose your own desktop over RDP.
• Pick only what you need. Every subsystem is a separate crate behind a feature flag, so a headless screenshot tool does not pull in audio, clipboard, or a GUI stack.

Features

Protocol and security

• RDP connection sequence: X.224 negotiation, MCS, capability exchange, licensing, reactivation
• Enhanced RDP Security with TLS (1.2 and 1.3)
• Network Level Authentication (NLA) via CredSSP, with NTLM and Kerberos
• KDC proxy and RDCleanPath support for gateway-mediated, just-in-time connections
• Terminal Services Gateway (MS-TSGU) transport
• .rdp file parsing and writing, plus a typed configuration property store

Graphics

• Client-side decoding: uncompressed raw bitmaps, Interleaved RLE, RDP 6.0 bitmap compression, and RemoteFX (RFX)
• Server-side encoding: RDP 6.0 bitmap compression, RemoteFX, optional NSCodec, and optional QOI / QOI+zstd
• Additional codec primitives available as libraries: ClearCodec, RemoteFX Progressive, ZGFX, and the graphics pipeline (EGFX) PDUs
• Bulk compression: MPPC, NCRUSH, and XCRUSH

Virtual channels

• Static (SVC) and dynamic (DVC / DRDYNVC) channel infrastructure
• Clipboard redirection (CLIPRDR), audio output (RDPSND), device and smart card redirection (RDPDR)
• Display control for dynamic resizing, echo (RTT probes), alternative input, and USB redirection
• Windows DVC COM plugin loader and a DVC named-pipe proxy for bridging external processes

Targets and bindings

• Native clients on Windows, macOS, and Linux
• WebAssembly bindings plus a protocol-agnostic web component (@devolutions/iron-remote-desktop)
• C#/.NET bindings generated with Diplomat (Devolutions.IronRdp)

Getting started

Prebuilt binaries

Checksummed .tar.gz archives are attached to each GitHub Release, one per supported platform:

• ironrdp-viewer — a windowed RDP client (tags ironrdp-viewer-v*)
• ironrdp-agent — a daemon-backed CLI for automation (tags ironrdp-agent-v*)

Download, checksum, and extraction instructions are included in each release's notes on the Releases page.

Install with Cargo

cargo install ironrdp-viewer
cargo install ironrdp-agent

Both binaries link native audio, so Linux builds need the ALSA development headers (libasound2-dev on Debian/Ubuntu) and Windows builds need NASM.

ironrdp-viewer

ironrdp-viewer is a portable, windowed RDP client that uses asynchronous I/O and software rendering.

ironrdp-viewer <HOSTNAME> --username <USERNAME> --password <PASSWORD>

Omitted credentials are prompted for interactively. You can also load a .rdp file:

ironrdp-viewer --rdp-file ./my-server.rdp

Set IRONRDP_LOG to adjust logging, e.g. IRONRDP_LOG="info,ironrdp_connector=trace". See the viewer README for the supported .rdp properties, TLS key logging, and the full option list.

ironrdp-agent

ironrdp-agent combines a long-lived RDP daemon with short-lived CLI invocations, which makes it convenient for scripts and LLM-driven automation:

ironrdp-agent daemon-start --overlay ./credentials.rdp        # in one terminal
ironrdp-agent connect --server <HOSTNAME> --username <USER>   # in another
ironrdp-agent screenshot ./desktop.png

connect fails with missing required fields unless credentials are available, so either preload them into the daemon with daemon-start --overlay <FILE> — which keeps secrets away from the IPC caller — or pass --password to connect.

Run ironrdp-agent --help-agent for a machine-readable description of every operation, and see the agent README for the IPC format, secret handling, and remote execution support.

Using IronRDP as a library

Add the meta crate and enable only the pieces you need:

[dependencies]
ironrdp = { version = "0.17", features = ["connector", "session", "graphics"] }

Each feature maps to a standalone crate, so you can also depend on ironrdp-pdu, ironrdp-connector, ironrdp-session, and friends directly. API documentation lives on docs.rs.

Two runnable examples ship with the meta crate:

# Connect, decode the desktop, and write a PNG. Blocking, synchronous I/O.
cargo run --example=screenshot -- --host <HOSTNAME> -u <USERNAME> -p <PASSWORD> -o out.png

# A minimal RDP server built on ironrdp-server.
cargo run --example=server -- --bind-addr 127.0.0.1:3389

Tips

Enabling RemoteFX on a Windows server

Run the following PowerShell commands, then reboot:

Set-ItemProperty -Path 'HKLM:\Software\Policies\Microsoft\Windows NT\Terminal Services' -Name 'ColorDepth' -Type DWORD -Value 5
Set-ItemProperty -Path 'HKLM:\Software\Policies\Microsoft\Windows NT\Terminal Services' -Name 'fEnableVirtualizedGraphics' -Type DWORD -Value 1

Alternatively, enable the following group policies with gpedit.msc and reboot. All of them live under Computer Configuration → Administrative Templates → Windows Components → Remote Desktop Services → Remote Desktop Session Host → Remote Session Environment:

1. RemoteFX for Windows Server 2008 R2 → Configure RemoteFX
2. Enable RemoteFX encoding for RemoteFX clients designed for Windows Server 2008 R2 SP1
3. Limit maximum color depth

Who uses IronRDP

• Devolutions Gateway for browser-based and native RDP client access
• Cloudflare Access for browser-based RDP
• Teleport for its remote desktop web access
• Lamco RDP Server, a Wayland-native RDP server for Linux desktop sharing
• MacRDP, a native RDP server for macOS
• qemu-rdp, an RDP server for QEMU displays
• A growing set of community projects building RDP servers and clients on top of the crate suite

Rust version (MSRV)

IronRDP libraries follow a conservative Minimum Supported Rust Version policy. The MSRV is the oldest stable Rust release that is at least 6 months old, bounded by the Rust version available in Debian stable-backports and Fedora stable. The toolchain pinned in rust-toolchain.toml is both the project toolchain and the MSRV validated by CI. See ARCHITECTURE.md for the full policy.

Contributing

Contributions are welcome. Start with ARCHITECTURE.md and STYLE.md, and keep changes scoped.

Project automation lives in xtask, following the cargo xtask convention. Run cargo xtask --help for the full list, cargo xtask bootstrap to install the development requirements, and cargo xtask ci before opening a pull request — it runs everything CI does except the FFI and .NET checks, which have their own cargo xtask ffi commands.

Building the workspace needs the ALSA development headers on Linux (libasound2-dev on Debian/Ubuntu) and NASM on Windows. The web client additionally needs Node.js >= 24 LTS, and the FFI bindings need the .NET SDK.

AI-assisted development

AI-assisted development is encouraged when used thoughtfully. Contributors remain responsible for understanding, reviewing, and validating every change produced with AI assistance.

For RDP protocol work, install the Windows Protocols skill so AI agents can navigate the Microsoft Open Specifications corpus. It significantly improves the correctness of AI-assisted work involving RDP protocol details. See awakecoding/openspecs for installation instructions.

Getting help

• Report bugs in the issue tracker
• Discuss the project in the Matrix room

License

Licensed under either of MIT or Apache-2.0 at your option.