SOCKS5 Proxy Server

A lightweight, fast and secure SOCKS5 proxy server implementation in Go with IP-based access control.

Features

• Full SOCKS5 protocol support for TCP connections
• IP-based access control using CIDR notation
• Support for both IPv4 and IPv6 addresses
• Domain name resolution support
• Debug mode for troubleshooting

Installation

# Clone the repository
git clone https://github.com/J4GL/proxy.git
cd proxy

# Build the binary
go build

Usage

Start the proxy server:

# Start with default settings
./proxy

# Start with debug mode enabled
./proxy -debug

The server will listen on the port specified in config.json (default: 1080).

Configuration

The server uses a config.json file to specify allowed IP ranges in CIDR notation. Example configuration:

{
  "port": 1080,
  "ipv4": [
    "127.0.0.1/32",
    "192.168.0.0/16",
    "10.0.0.0/8"
  ],
  "ipv6": [
    "::1/128",
    "fe80::/10"
  ]
}

Configuration options:

• port: The TCP port number the proxy server will listen on (default: 1080)
• ipv4: List of allowed IPv4 CIDR ranges
• ipv6: List of allowed IPv6 CIDR ranges

Only clients with IP addresses within these ranges will be allowed to connect to the proxy server.

Debug Mode

Start the server with the -debug flag to enable verbose logging:

./proxy -debug

This will output detailed information about:

• Client connections and IP verification
• SOCKS5 protocol negotiations
• Connection establishment status
• Data transfer errors

Protocol Support

The server implements the SOCKS5 protocol with the following features:

• No authentication required
• TCP CONNECT command support
• IPv4, IPv6, and domain name address types

Security Considerations

• The server does not implement authentication - access control is purely IP-based
• Only TCP CONNECT method is supported (no UDP or BIND)
• Configure your firewall to restrict access to port 1080
• Regularly review and update the allowed IP ranges in config.json

Testing

Run the test suite:

go test

Speedtest

On a Macmini M4 with 10Gb ethernet port and 8Gb internet.