GO Simple Tunnel (GOST)

GOST can be used in three primary modes:

1. Proxy: Acts as a proxy service to access the network. Multiple protocols can be combined to form a forwarding chain for traffic.
2. Port Forwarding: Maps the port of one service to the port of another service. Like the proxy mode, it supports multi-level forwarding chains using various protocols.
3. Reverse Proxy: Uses tunnels and intranet penetration to expose local services located behind a NAT or firewall to the public network.

GOST is a feature-rich tunneling tool. Key capabilities include:

Core Features

• Multi-port listening and multi-level forwarding chains.
• Support for multiple protocols and TCP/UDP port forwarding.
• Reverse proxy and tunneling for intranet penetration.
• TCP/UDP transparent proxy (redirect).
• DNS resolution and proxying.
• TUN/TAP device support and TUN2SOCKS.
• Load balancing, route control, and admission control.
• Rate limiting (speed/flow control).
• Plugin system and dynamic configuration via Web API.
• Prometheus metrics monitoring.

Management Tools

• GUI: gostctl
• WebUI: gost-ui
• Android Plugin: ShadowsocksGostPlugin for Shadowsocks on Android.

GOST provides a wide range of networking and tunneling capabilities, including:

• Traffic Control: Load balancing, routing control (bypass), admission control, and bandwidth/rate limiting.
• Networking: TCP/UDP port forwarding, TCP/UDP transparent proxy, DNS resolver and proxy, and TUN/TAP device support (including TUN2SOCKS).
• Advanced Tunneling: Multi-level forwarding chains, Reverse Proxy, and Reverse Tunnel.
• Extensibility: Plugin system, Web API, and Dynamic configuration.
• Observability: Prometheus metrics.
• Interfaces: GUI (gostctl) and WebUI (gost-ui).

You can install GOST using several methods: binary files, installation scripts, source compilation, or Docker.

Installation Methods

1. Installation Script To install the latest version automatically:

bash <(curl -fsSL https://github.com/go-gost/gost/raw/master/install.sh) --install

To select a specific version during installation:

bash <(curl -fsSL https://github.com/go-gost/gost/raw/master/install.sh)

2. Source Compilation Clone the repository and build the binary using Go:

git clone https://github.com/go-gost/gost.git
cd gost/cmd/gost
go build

3. Docker Run the Docker image to verify installation:

docker run --rm gogost/gost -V

4. Binary Files Download pre-compiled binaries from the official releases page.

The GO Simple Tunnel process supports dynamic configuration reloading without a full restart using two methods:

1. SIGHUP Signal: Sending a SIGHUP signal to the running process triggers a configuration reload.
2. Auto Reload: If the reload interval is configured, the application will automatically reload the configuration at the specified time intervals.

When a reload is triggered, the application parses the new configuration, loads the services, and restarts the service layer to match the new settings.

GO Simple Tunnel supports several built-in management services that can be enabled via configuration:

• API Service: Provides an interface for managing the instance. It can be configured with a specific address (supporting tcp or unix:// prefixes), a PathPrefix, AccessLog settings, and authentication via Auth strings or a named Auther.
• Metrics Service: Exposes operational metrics. It supports a specific address (supporting tcp or unix:// prefixes), a Path, and authentication via Auth strings or a named Auther.
• Profiling Service: Enables Go profiling. By default, it listens on :6060 if no address is provided.

You can run multiple GOST worker processes within a single command execution by using the -- separator. Each segment separated by -- will be treated as a distinct worker process. This allows for running multiple service configurations or node chains in one command execution.

Example usage:

gost -L proxy://:8080 -- -L proxy://:8081

The gost binary provides several flags to configure services, nodes, configuration sources, and monitoring endpoints.

Configuration Flags

• -L <service>: Specify a list of services to run.
• -F <node>: Specify a list of chain nodes.
• -C <config>: Provide one or more configuration files, URLs, or inline JSON strings.
• -O <format>: Set the output format to yaml or json.
• -R <duration>: Set an auto-reload period (e.g., 30s, 1m).

Monitoring and Debugging

• -D: Enable debug mode.
• -DD: Enable trace mode.
• --api <address>: Set the API service address.
• --metrics <address>: Set the metrics service address.
• -V: Print the version and exit.