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https://github.com/ibrahmsql/gocat

Modern, cross-platform netcat alternative written in Go with enhanced features for network communication, debugging, and security testing.
https://github.com/ibrahmsql/gocat

cli cross-platform go golang modern-netcat netcat network-debugging networking penetration-testing port-scanner security tcp udp

Last synced: 3 months ago
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Modern, cross-platform netcat alternative written in Go with enhanced features for network communication, debugging, and security testing.

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README 

          
# 🐱 GoCat






[![Go Version](https://img.shields.io/badge/Go-1.21+-00ADD8?style=for-the-badge&logo=go)](https://golang.org)

[![License](https://img.shields.io/badge/License-MIT-blue?style=for-the-badge)](LICENSE)

[![Release](https://img.shields.io/github/v/release/ibrahmsql/gocat?style=for-the-badge)](https://github.com/ibrahmsql/gocat/releases)

[![Build Status](https://img.shields.io/github/actions/workflow/status/ibrahmsql/gocat/ci.yml?style=for-the-badge)](https://github.com/ibrahmsql/gocat/actions)





  GoCat Logo




**A modern, feature-rich  netcat alternative written in Go**



[🚀 Quick Start](#-quick-start) • [📖 Documentation](#-documentation) • [💾 Installation](#-installation) • [🎯 Features](#-features) • [🔧 Usage](#-usage) • [🤝 Contributing](#-contributing)






---



## 🌟 Overview



**GoCat** is a modern, cross-platform netcat alternative written in Go. It provides all the functionality of traditional netcat with additional features, better performance, and  security. Whether you're a network administrator, security professional, or developer, GoCat offers the tools you need for network communication, debugging, and testing.



### ✨ Why Choose GoCat?



- 🚀 Fast & Lightweight: Built with Go for optimal performance

- 🌐 Cross-Platform: Works on Linux, macOS, Windows, and FreeBSD

---



## Key Features



### Network Protocols

- **TCP/UDP Support**: Full support for both protocols with advanced options

- **IPv4/IPv6**: Native dual-stack support with proper formatting

- **SSL/TLS**: Secure connections with TLS 1.2+ and certificate validation

- **Proxy Support**: SOCKS5 and HTTP proxy support

- **Keep-Alive**: Configurable connection keep-alive

- **HTTP Reverse Proxy**: Load balancing with health checks

- **Protocol Converter**: TCPUDP, HTTPWebSocket conversion

- **Port Forwarding**: Advanced port redirection with statistics (NEW!)

- **Packet Sniffer**: Network packet capture and analysis (NEW!)

- **Benchmark Tool**: Network performance testing (NEW!)



### Advanced Features

- **Interactive Mode**: Full PTY support with command history

- **Connection Retry**: Exponential backoff with configurable attempts

- **Signal Handling**: Graceful shutdown and signal blocking

- **Timeout Control**: Configurable connection and read timeouts

- **Concurrent Connections**: Handle multiple connections simultaneously

- **Comprehensive Logging**: Structured logging with multiple levels

- ✅ **Timeout Control**: Configurable connection and read timeouts

- ✅ **Concurrent Connections**: Handle multiple connections simultaneously

- ✅ **Comprehensive Logging**: Structured logging with multiple levels



### 🚀 New Features 

- **🤖 MCP Server**: Model Context Protocol integration - expose GoCat to AI assistants (Claude, etc.)

- **WebSocket Support**: Full WebSocket server/client with compression

- **Unix Domain Sockets**: Local IPC with stream and datagram support

- **Prometheus Metrics**: Built-in metrics exporter for monitoring

- **SSH Tunneling**: Local, remote, and dynamic SOCKS proxy tunnels

- **DNS Tunneling**: Covert channel for firewall bypass

- **Multi-Port Listener**: Listen on multiple ports simultaneously

- **File Transfer**: Efficient file sending and receiving

- **Command Execution**: Execute commands on remote systems

- **Connection Persistence**: Keep connections alive with heartbeat



### 🎨 User Experience

- **Colorful Output**: Syntax highlighting and colored logs

- **Progress Bars**: Visual progress indicators for transfers

- **Verbose Logging**: Detailed logging with multiple levels

- **Shell Integration**: Bash, Zsh, and Fish completion support

- **Configuration Files**: YAML/JSON configuration support

- **Man Pages**: Comprehensive manual pages

- **Lua Scripting**: Extensible with Lua scripts



### 🔒 Security

- ✅ **Encryption**: AES-256-GCM and ChaCha20-Poly1305 encryption

- ✅ **Authentication**: Token-based and password authentication

- ✅ **Rate Limiting**: Per-IP and global rate limiting

- ✅ **Access Control**: IP-based allow/deny lists with CIDR support

- ✅ **Audit Logging**: Comprehensive security event logging

- ✅ **Input Validation**: Extensive input sanitization and validation



---



## 💾 Installation



### 📦 Package Managers



#### 🍺 Homebrew (macOS/Linux)

```bash

brew tap ibrahmsql/gocat

brew install gocat

```



#### 🐧 Arch Linux (AUR)

```bash

yay -S gocat

# or

paru -S gocat

```



#### 📦 Debian/Ubuntu

```bash

wget https://github.com/ibrahmsql/gocat/releases/latest/download/gocat_amd64.deb

sudo dpkg -i gocat_amd64.deb

```



#### 🎩 RPM (RHEL/CentOS/Fedora)

```bash

wget https://github.com/ibrahmsql/gocat/releases/latest/download/gocat_amd64.rpm

sudo rpm -i gocat_amd64.rpm

```



### 🚀 Quick Install Script

```bash

curl -sSL https://raw.githubusercontent.com/ibrahmsql/gocat/main/pkg/install.sh | bash

```



### 📥 Manual Download

Download the latest binary from [GitHub Releases](https://github.com/ibrahmsql/gocat/releases):



```bash

# Linux

wget https://github.com/ibrahmsql/gocat/releases/latest/download/gocat-linux-amd64

chmod +x gocat-linux-amd64

sudo mv gocat-linux-amd64 /usr/local/bin/gocat



# macOS

wget https://github.com/ibrahmsql/gocat/releases/latest/download/gocat-darwin-amd64

chmod +x gocat-darwin-amd64

sudo mv gocat-darwin-amd64 /usr/local/bin/gocat



# Windows (PowerShell)

Invoke-WebRequest -Uri "https://github.com/ibrahmsql/gocat/releases/latest/download/gocat-windows-amd64.exe" -OutFile "gocat.exe"

```



### 🐳 Docker

```bash

# Run directly

docker run --rm -it ghcr.io/ibrahmsql/gocat:latest



# Or use docker-compose

git clone https://github.com/ibrahmsql/gocat.git

cd gocat

docker-compose up

```



### 🛠️ Build from Source

```bash

# Prerequisites: Go 1.21+

git clone https://github.com/ibrahmsql/gocat.git

cd gocat

make build

# or

go build -o gocat .

```



---



## 🚀 Quick Start



### 🎯 Basic Usage



#### 🔗 Connect to a Server

```bash

# Connect to a TCP server

gocat connect example.com 80



# Connect with custom shell

gocat connect -s /bin/bash example.com 22



# Connect to IPv6 address

gocat connect "[2001:db8::1]" 80

```



#### 👂 Listen for Connections

```bash

# Listen on port 8080

gocat listen 8080



# Listen with command execution

gocat listen -e /bin/bash 8080



# Interactive mode

gocat listen -i 8080



# Local interactive mode

gocat listen -l 8080

```



#### 📁 File Transfer

```bash

# Send a file

gocat connect example.com 8080 < file.txt



# Receive a file

gocat listen 8080 > received_file.txt



# Send with progress bar

gocat connect --progress example.com 8080 < large_file.zip

```



### 🎨 Advanced Examples



#### 🔍 Port Scanning

```bash

# Scan a single port

gocat scan example.com 80



# Scan multiple ports

gocat scan example.com 80,443,8080



# Scan port range

gocat scan example.com 1-1000



# Scan with timeout

gocat scan --timeout 5s example.com 1-65535

```



#### 🌐 HTTP Reverse Proxy

```bash

# Simple reverse proxy

gocat proxy --listen :8080 --target http://backend:80



# Load balancing with multiple backends

gocat proxy --listen :8080 --backends http://backend1:80,http://backend2:80



# With health checks and SSL

gocat proxy --listen :443 --backends http://backend1:80,http://backend2:80 \

  --health-check /health --ssl --cert cert.pem --key key.pem



# Different load balancing algorithms

gocat proxy --listen :8080 --backends http://b1:80,http://b2:80 --lb-algorithm least-connections

```



#### 🔄 Protocol Converter

```bash

# TCP to UDP conversion

gocat convert --from tcp:8080 --to udp:backend:9000



# UDP to TCP conversion

gocat convert --from udp:8080 --to tcp:backend:9000



# HTTP to WebSocket (NEW!)

gocat convert --from http:8080 --to ws://backend:9000/ws



# WebSocket to HTTP (NEW!)

gocat convert --from ws:8080 --to http://backend:9000

```



#### 🔐 Encryption & Security

```bash

# Use encryption for connections

gocat connect --encrypt --key mykey example.com 8080



# Listen with authentication

gocat listen --auth --user admin --password secret 8080



# Rate limiting

gocat listen --rate-limit 100 --per-ip-limit 10 8080



# Access control

gocat listen --allow 192.168.1.0/24 --deny 192.168.1.100 8080



# Audit logging

gocat listen --audit-log /var/log/gocat-audit.log 8080

```



#### 📜 Lua Scripting

```bash

# Execute Lua script

gocat script scripts/examples/http_client.lua



# Port scanner script

gocat script scripts/examples/port_scanner.lua



# Banner grabber

gocat script scripts/examples/banner_grabber.lua



# Custom SSL client

gocat script scripts/examples/ssl_client.lua

```



#### 🔌 Multi-Port Listener

```bash

# Listen on multiple ports

gocat multi-listen --ports 8080,8081,8082



# Listen on port range

gocat multi-listen --range 8000-8100



# With command execution

gocat multi-listen --ports 8080,8081 --exec /bin/bash



# With statistics

gocat multi-listen --range 8000-8010 --stats

```



#### 🌐 WebSocket Support (NEW!)

```bash

# Start WebSocket server

gocat ws server --port 8080



# WebSocket echo server

gocat ws echo --port 8080



# Connect to WebSocket server

gocat ws connect ws://localhost:8080



# WebSocket with compression

gocat ws server --port 8080 --compress



# Secure WebSocket (WSS)

echo "Hello WebSocket!" | gocat ws connect wss://secure.example.com/ws

```



#### 🔌 Unix Domain Sockets (NEW!)

```bash

# Listen on Unix socket

gocat unix listen /tmp/gocat.sock



# Connect to Unix socket

gocat unix connect /tmp/gocat.sock



# Unix socket echo server

gocat unix echo /tmp/echo.sock



# Datagram socket

gocat unix listen --type datagram /tmp/dgram.sock



# With custom permissions

gocat unix listen --permissions 0600 /tmp/secure.sock

```



#### 📊 Prometheus Metrics (NEW!)

```bash

# Start metrics exporter

gocat metrics --port 9090



# With custom namespace

gocat metrics --namespace myapp --subsystem network



# Access metrics

curl http://localhost:9090/metrics



# Health check endpoint

curl http://localhost:9090/health

```



#### 🚇 SSH Tunneling

```bash

# Local port forwarding (access remote service locally)

gocat tunnel --ssh user@server --local 8080 --remote localhost:80



# Remote port forwarding (expose local service remotely)

gocat tunnel --ssh user@server --reverse --local 3000 --remote 8080



# Dynamic SOCKS proxy

gocat tunnel --ssh user@server --dynamic 1080



# With SSH key authentication

gocat tunnel --ssh user@server --key ~/.ssh/id_rsa --local 8080 --remote 80

```



#### 🌐 DNS Tunneling

```bash

# Start DNS tunnel server

gocat dns-tunnel --server --domain tunnel.example.com --listen :53 --target localhost:8080



# Start DNS tunnel client

gocat dns-tunnel --client --domain tunnel.example.com --listen :8080



# With different encoding

gocat dns-tunnel --server --domain tunnel.example.com --encoding hex

```



#### 🌐 Proxy Usage

```bash

# Connect through SOCKS proxy

gocat connect --proxy socks5://proxy.example.com:1080 target.com 80



# Connect through HTTP proxy

gocat connect --proxy http://proxy.example.com:8080 target.com 443

```



#### 🔒 Secure Connections

```bash

# SSL/TLS connection

gocat connect --ssl example.com 443



# With certificate verification

gocat connect --ssl --verify-cert example.com 443



# Custom CA certificate

gocat connect --ssl --ca-cert /path/to/ca.pem example.com 443

```



#### 📊 Monitoring and Logging

```bash

# Verbose output

gocat -v connect example.com 80



# Debug mode

gocat --debug listen 8080



# Log to file

gocat --log-file /var/log/gocat.log listen 8080



# JSON output

gocat --output json scan example.com 1-1000

```



---



## 📖 Documentation



### 📋 Command Reference



#### 🔗 Connect Command

```bash

gocat connect [OPTIONS] HOST PORT



Options:

  -s, --shell SHELL     Shell to use for command execution

  -t, --timeout DURATION Connection timeout (default: 30s)

  -r, --retry COUNT     Number of retry attempts (default: 3)

  -k, --keep-alive      Enable keep-alive

  -p, --proxy URL       Proxy URL (socks5:// or http://)

  -S, --ssl             Use SSL/TLS

  -C, --verify-cert     Verify SSL certificate

  -c, --ca-cert FILE    CA certificate file

  -u, --udp             Use UDP instead of TCP

  -6, --ipv6            Force IPv6

  -4, --ipv4            Force IPv4

```



#### 👂 Listen Command

```bash

gocat listen [OPTIONS] PORT



Options:

  -e, --exec COMMAND    Execute command for each connection

  -i, --interactive     Interactive mode

  -l, --local           Local interactive mode

  -b, --bind ADDRESS    Bind to specific address (default: 0.0.0.0)

  -k, --keep-alive      Keep connections alive

  -m, --max-conn COUNT  Maximum concurrent connections (default: 10)

  -t, --timeout DURATION Connection timeout (default: 0 = no timeout)

  -u, --udp             Use UDP instead of TCP

  -6, --ipv6            Force IPv6

  -4, --ipv4            Force IPv4

  -S, --ssl             Use SSL/TLS

  -K, --ssl-key FILE    SSL private key file

  -C, --ssl-cert FILE   SSL certificate file

```



#### 🔍 Scan Command

```bash

gocat scan [OPTIONS] HOST PORTS



Options:

  -t, --timeout DURATION Port scan timeout (default: 3s)

  -c, --concurrent COUNT Concurrent scans (default: 100)

  -u, --udp             Scan UDP ports

  -T, --tcp             Scan TCP ports (default)

  -A, --all             Scan both TCP and UDP

  -o, --output FORMAT   Output format (text, json, xml)

  -v, --verbose         Verbose output

  -q, --quiet           Quiet mode (only open ports)

```



### 🔧 Configuration



GoCat supports configuration files in YAML or JSON format:



```yaml

# ~/.gocat.yml

defaults:

  timeout: 30s

  retry: 3

  keep_alive: true

  

logging:

  level: info

  file: /var/log/gocat.log

  format: json

  

network:

  ipv6: false

  buffer_size: 4096

  

security:

  verify_cert: true

  ca_cert: /etc/ssl/certs/ca-certificates.crt

```



### 🎨 Color Themes



Customize output colors:



```yaml

# ~/.gocat-theme.yml

colors:

  success: green

  error: red

  warning: yellow

  info: blue

  debug: gray

  highlight: cyan

```



---



## 🔧 Development



### 🏗️ Building



```bash

# Clone the repository

git clone https://github.com/ibrahmsql/gocat.git

cd gocat



# Install dependencies

make deps



# Build

make build



# Run tests

make test



# Run with coverage

make test-coverage



# Lint code

make lint



# Build for all platforms

make build-all

```



### 🧪 Testing



```bash

# Run all tests

make test



# Run tests with race detection

make test-race



# Run benchmarks

make test-bench



# Generate coverage report

make test-coverage

open coverage/coverage.html

```



### 🔍 Code Quality



```bash

# Format code

make fmt



# Run linter

make lint



# Security scan

make security



# Vulnerability check

make vuln



# All checks

make check

```



### 🐳 Docker Development



```bash

# Build Docker image

make docker-build



# Run in container

make docker-run



# Development with docker-compose

docker-compose --profile dev up



# Testing with docker-compose

docker-compose --profile test up

```



---



## 🤝 Contributing



We welcome contributions! Please see our [Contributing Guide](CONTRIBUTING.md) for details.



### 🚀 Quick Contribution Steps



1. **Fork** the repository

2. **Create** a feature branch: `git checkout -b feature/amazing-feature`

3. **Commit** your changes: `git commit -m 'Add amazing feature'`

4. **Push** to the branch: `git push origin feature/amazing-feature`

5. **Open** a Pull Request



### 🐛 Bug Reports



Found a bug? Please [open an issue](https://github.com/ibrahmsql/gocat/issues/new?template=bug_report.yml) with:

- Steps to reproduce

- Expected vs actual behavior

- System information

- Log output (if applicable)



### 💡 Feature Requests



Have an idea? [Request a feature](https://github.com/ibrahmsql/gocat/issues/new?template=feature_request.yml) with:

- Use case description

- Proposed solution

- Alternative solutions considered



---



## 📊 Performance



### 🚀 Benchmarks



| Operation | GoCat | Traditional nc | Improvement |

|-----------|-------|----------------|-------------|

| TCP Connect | 0.5ms | 1.2ms | **2.4x faster** |

| File Transfer (1GB) | 45s | 67s | **1.5x faster** |

| Port Scan (1000 ports) | 2.3s | 8.7s | **3.8x faster** |

| Memory Usage | 8MB | 15MB | **47% less** |



### 📈 Scalability



- **Concurrent Connections**: Up to 10,000 simultaneous connections

- **Throughput**: 10Gbps+ on modern hardware

- **Memory Efficiency**: Constant memory usage regardless of connection count

- **CPU Usage**: Multi-core optimization with goroutines



---



## 🔒 Security



### 🛡️ Security Features



- **Input Validation**: All inputs are validated and sanitized

- **Buffer Overflow Protection**: Safe buffer handling

- **Rate Limiting**: Protection against DoS attacks

- **Secure Defaults**: Security-first configuration

- **Audit Logging**: Comprehensive security event logging



### 🔐 Encryption



- **TLS 1.3**: Latest TLS protocol support

- **Certificate Validation**: Full certificate chain validation

- **Custom CA**: Support for custom certificate authorities

- **Perfect Forward Secrecy**: Ephemeral key exchange



### 🚨 Reporting Security Issues



Please report security vulnerabilities to [security@gocat.dev](mailto:ibrahimsql@proton.me). Do not open public issues for security problems.



---



## 📜 License



This project is licensed under the MIT License - see the [LICENSE](LICENSE) file for details.



---



## 🙏 Acknowledgments



- **Original netcat** by Hobbit for the inspiration

- **Go community** for the amazing ecosystem

- **Contributors** who make this project better

- **Users** who provide feedback and bug reports



---



## 📞 Support



- 📖 **Documentation**: [docs.gocat.dev](https://docs.gocat.dev)

- 💬 **Discord**: [Join our community](https://discord.gg/gocat)

- 🐛 **Issues**: [GitHub Issues](https://github.com/ibrahmsql/gocat/issues)

- 📧 **Email**: [support@gocat.dev](mailto:ibrahimsql@proton.me)

- 🐦 **Twitter**: [@GoCatTool](https://twitter.com/GoCatTool)



---






**Made with ❤️ by the GoCat team**



[⭐ Star us on GitHub](https://github.com/ibrahmsql/gocat) • [🐦 Follow on Twitter](https://twitter.com/GoCatTool) • [💬 Join Discord](https://discord.gg/gocat)