proxychains-rs (v5.0.0)

This document is a concise usage and build guide for the proxychains-rs repository (version 5.0.0). It focuses on building, running and debugging the Rust implementation that provides proxychains-compatible behavior, and also covers common issues.

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Overview

proxychains-rs (v5.0.0) is a Rust implementation that aims to be compatible with existing proxychains behavior. Its goal is to produce a shared library that can be injected into target programs using LD_PRELOAD and that behaves (including textual output) consistently with prior implementations. The runtime artifact produced by this project is libproxychains_rs.so.

Main runtime artifact (release):

• target/release/libproxychains_rs.so — the shared object produced by Rust (cdylib).

Note: The supported runtime artifact is target/release/libproxychains_rs.so. The project does not rely on producing a compatibility copy named libproxychains4.so by default anymore.

Tip: this repository contains a rust-toolchain pin (nightly). Cargo will automatically use the pinned nightly toolchain when building the project.

Important: the repository uses some Rust nightly-only features in parts of the codebase (for example c_variadic / extern_types). Because of this, a nightly toolchain is required to build.

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Local build (recommended)

1. Ensure you have rustup installed and enable the nightly toolchain:

rustup toolchain install nightly

2. Build the project using cargo from the proxychains-rs directory:

# Build the Rust portion using the nightly toolchain
rustup run nightly cargo build -p proxychains_rs --release

This will produce the shared object under target/release/libproxychains_rs.so.

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Using with a target program (example)

To use proxychains-rs with any dynamically linked program that supports LD_PRELOAD, set the configuration file path and LD_PRELOAD the built shared object:

PROXYCHAINS_CONF_FILE=/etc/proxychains.conf LD_PRELOAD=target/release/libproxychains_rs.so curl -I https://www.baidu.com

If you are replacing an existing proxychains4 script or binary (the C-based tool), the Rust version aims to be consistent in behavior and log text. Using target/release/libproxychains_rs.so as LD_PRELOAD should act as a drop-in replacement for the C artifact.

An example wrapper similar to /usr/bin/proxychains:

#!/bin/sh
echo "ProxyChains-5.0"
if [ $# = 0 ]; then
    echo "\tusage:"
    echo "\t\tproxychains <prog> [args]"
    exit
fi
export LD_PRELOAD=libproxychains_rs.so
exec "$@"

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Configuration and debugging options

• Configuration file search order (priority):

  1. PROXYCHAINS_CONF_FILE environment variable (or -f argument)
  2. ./proxychains.conf in the current directory
  3. $(HOME)/.proxychains/proxychains.conf
  4. System config /etc/proxychains.conf (sysconfdir)

• Settings in the configuration file:

  • quiet_mode — suppresses the per-connection log lines (same as the C implementation).
  • proxy_dns, proxy_dns_daemon, proxy_dns_old — control remote-DNS (RDNS) behavior/modes.

• Environment variables:

  • PROXYCHAINS_VERBOSE_DEBUG=1 — enable extra internal debug traces for development and troubleshooting.

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Frequently Asked Questions

• Q: Why is a nightly toolchain required to build?
  • A: The port uses Rust features that are currently only available on the nightly channel (for example c_variadic / extern_types). That's why the nightly toolchain is required.

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Future improvements (suggestions)

• Reduce or remove unsafe and static mut usage where practical and refactor key paths to be more idiomatic Rust (long-term goal).
• Improve cross-platform support.

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