A comprehensive command-line tool written in Rust for testing network connectivity, DNS resolution, and network path characteristics across IPv4 and IPv6.

Key Features:

🌐 Comprehensive IPv4/IPv6 connectivity testing
🔍 Advanced DNS testing with sinkhole detection
📊 MTU discovery and path analysis
🛡️ DNS filtering effectiveness analysis
🚀 High-performance async implementation
📋 Human-readable and JSON output formats

Quick Start

# Clone and build
git clone https://github.com/your-username/nettest.git
cd nettest && cargo build --release

# Run comprehensive tests
./target/release/nettest full google.com

# Test DNS with IPv6
./target/release/nettest network ping google.com --ip-version v6

# Check DNS filtering effectiveness  
./target/release/nettest dns filtering

Features

Network Testing

IPv4 and IPv6 support - Test connectivity using both IP versions
Multiple protocols - Support for TCP, UDP, and ICMP
Port testing - Test common ports and custom port ranges
Timeout configuration - Configurable timeouts for all tests

MTU Discovery

Binary search MTU discovery - Efficiently find the maximum MTU size
Common MTU testing - Test standard MTU sizes (68, 576, 1280, 1500, 4464, 9000)
Custom range testing - Test specific MTU ranges
IPv4 and IPv6 support - MTU discovery for both IP versions

DNS Testing

Comprehensive record types - A, AAAA, MX, NS, TXT, CNAME, SOA, PTR, and more
Multiple DNS servers - Test against Google, Cloudflare, Quad9, OpenDNS, and others
TCP and UDP queries - Support for both DNS transport protocols
Sinkhole detection - Automatically detects DNS sinkholing (0.0.0.0, 127.0.0.1, etc.)
Smart error handling - Distinguishes between DNS failures and missing records
System DNS integration - Uses system DNS configuration while avoiding search domain expansion
Large query testing - Test handling of large DNS responses
International domains - Support for IDN (Internationalized Domain Names)

Domain Category Testing

Normal websites - Test legitimate, commonly used sites
Ad networks - Test advertising and tracking domains
Spam domains - Test temporary email and spam-associated domains
Adult content - Test adult content sites (often filtered)
Malicious domains - Test known malicious/phishing domains
Social media - Test major social media platforms
Streaming services - Test video and music streaming sites
Gaming platforms - Test gaming services and platforms
News websites - Test major news and media sites

DNS Filtering Analysis

Filter effectiveness - Analyze how well DNS filtering is working
Category-based analysis - See which categories are being blocked
Detailed reporting - Get statistics on resolution success rates

Installation

From Source

# Clone the repository
git clone https://github.com/your-username/nettest.git
cd nettest

# Build the project
cargo build --release

# Install globally (optional)
cargo install --path .

Using Cargo

# Install directly from source (when published)
cargo install nettest

Requirements

Rust 1.70 or later
Root/administrator privileges may be required for:
- ICMP ping tests
- Raw socket operations
- Some MTU discovery operations

Usage

Basic Commands

# Run comprehensive tests on a target
nettest full google.com

# Test TCP connectivity
nettest network tcp google.com --port 80

# Test UDP connectivity  
nettest network udp 8.8.8.8 --port 53

# Ping test
nettest network ping google.com --count 4

# Test common ports
nettest network ports google.com --protocol tcp

# DNS query
nettest dns query google.com --record-type a

# Test DNS servers
nettest dns servers google.com

# Test domain categories
nettest dns categories --category normal

# MTU discovery
nettest mtu discover google.com

# Test common MTU sizes
nettest mtu common google.com

Advanced Options

# Specify IP version
nettest network tcp google.com --ip-version v4
nettest network tcp google.com --ip-version v6
nettest network tcp google.com --ip-version both

# Custom timeout
nettest --timeout 10 network tcp google.com

# JSON output
nettest --json dns query google.com

# Verbose logging
nettest --verbose full google.com

# DNS query with specific server
nettest dns query google.com --server 8.8.8.8:53 --tcp

# Custom MTU range
nettest mtu range google.com --min 1000 --max 1500

Domain Category Testing

Test different categories of domains to analyze DNS filtering:

# Test normal websites
nettest dns categories --category normal

# Test ad networks
nettest dns categories --category ads

# Test all categories
nettest dns categories --category all

# DNS filtering effectiveness
nettest dns filtering

# Show system DNS configuration
nettest dns debug

DNS Sinkhole Detection

NetTest automatically detects when domains are being sinkholed (redirected to special IP addresses):

# Example output showing sinkhole detection
$ nettest dns query blocked-domain.com --record-type a
PASS DNS A query for blocked-domain.com (UDP) (45ms)
  ✓ A records: 🕳️ SINKHOLED (security success): Redirected to sinkhole IPs: 0.0.0.0

# Example showing missing records (not an error)
$ nettest dns query image.example.com --record-type mx  
PASS DNS MX query for image.example.com (UDP) (32ms)
  ✓ MX records: (none - no mail servers configured)

Comprehensive Testing

The full command runs a comprehensive suite of tests:

# Full test suite for a domain
nettest full example.com

# Full test with specific IP version
nettest full example.com --ip-version v4

This includes:

TCP and UDP connectivity tests
ICMP ping tests
MTU discovery
DNS resolution tests
DNS server tests

Output Formats

Human-readable (default)

Colored, formatted output suitable for terminal viewing.

JSON

Machine-readable JSON output for integration with other tools:

nettest --json dns query google.com

Testing

Run the test suite:

# Unit tests
cargo test

# Integration tests
cargo test --test integration_tests

# All tests with verbose output
cargo test -- --nocapture

Architecture

NetTest is built with a modular architecture for maintainability and extensibility:

src/
├── cli/          # Command-line interface and argument parsing  
├── network/      # Network connectivity testing
│   ├── icmp.rs   # ICMP ping tests with IPv6 support
│   ├── tcp.rs    # TCP connection testing
│   └── udp.rs    # UDP connectivity testing
├── dns/          # DNS testing and analysis
│   ├── categories.rs  # Domain category definitions
│   ├── queries.rs     # DNS query implementations  
│   └── mod.rs         # Core DNS logic with sinkhole detection
├── mtu/          # MTU discovery and testing
├── utils/        # Common utilities and error handling
└── main.rs       # Application entry point and orchestration

Key Design Principles

Async-first: All network operations are asynchronous for better performance
Error handling: Comprehensive error handling with descriptive messages
Cross-platform: Works on macOS, Linux, and Windows
IPv6 ready: Full support for IPv6 alongside IPv4
Extensible: Easy to add new test types and protocols

Security Considerations

This tool is designed for defensive security testing and network diagnostics. It:

Tests legitimate connectivity to verify network functionality
Analyzes DNS filtering effectiveness
Discovers network path characteristics
Does not attempt to exploit or attack systems
Respects rate limits and timeouts

License

This project is licensed under the WTFPL (Do What The F*ck You Want To Public License) Version 2.

            DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
                    Version 2, December 2004

 Copyright (C) 2004 Sam Hocevar <sam@hocevar.net>

 Everyone is permitted to copy and distribute verbatim or modified
 copies of this license document, and changing it is allowed as long
 as the name is changed.

            DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
   TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION

  0. You just DO WHAT THE FUCK YOU WANT TO.

TL;DR: Do whatever you want with this code! 🎉

Contributing

Since this project is licensed under WTFPL, you can do whatever you want! But if you'd like to contribute:

Fork the repository
Create a feature branch: git checkout -b feature/amazing-feature
Make your changes and test: cargo test && cargo clippy
Commit your changes: git commit -m 'Add amazing feature'
Push to the branch: git push origin feature/amazing-feature
Open a Pull Request

Development Setup

# Clone your fork
git clone https://github.com/your-username/nettest.git
cd nettest

# Install development dependencies
cargo build

# Run all quality checks
cargo fmt           # Format code
cargo clippy        # Lint code  
cargo test          # Run tests
cargo audit         # Security audit

Code Quality

The project maintains high code quality standards:

✅ All tests must pass
✅ Zero clippy warnings
✅ Proper formatting with rustfmt
✅ No security vulnerabilities
✅ Comprehensive error handling

Changelog

Recent Improvements

🔧 Fixed IPv6 ping issues - IPv6 ICMP now works correctly on macOS
🛡️ Enhanced DNS security - Added sinkhole detection and improved error handling
📦 Updated dependencies - Migrated from trust-dns to hickory-dns for better maintenance
🎯 Improved accuracy - Fixed DNS search domain issues for more accurate testing
⚡ Better performance - Async implementation with proper timeout handling