Warning

This repository is my vibe code experiment and is not fully tested. Use at your own risk—features and behaviors may change or break unexpectedly.

QCat

QCat is a modern alternative to netcat with QUIC, TCP, and UDP support. The primary purpose is to learn about network programming in Go and analyze network packets via tools like Wireshark.

Features

• Support for QUIC protocol (default)
• TCP protocol support
• UDP protocol support
• Listen and connect modes
• Simple, easy-to-understand codebase for educational purposes

Installation

Prerequisites

• Go 1.18 or higher installed (https://golang.org/dl/)
• Git (for building from source)

Install via go install

go install github.com/zzdif/qcat@latest

Ensure $GOPATH/bin or $HOME/go/bin is in your PATH to use the installed binary.

Build from source

git clone https://github.com/zzdif/qcat.git
cd qcat
go build -o qcat

Optionally, move the binary to a directory in your PATH:

mv qcat $HOME/go/bin/

Usage

Listen mode (server)

# Listen on port 8000 with QUIC protocol (default)
./qcat listen -l :8000

# Listen using TCP
./qcat listen -l :8000 -p tcp

# Listen using UDP
./qcat listen -l :8000 -p udp

Idle Timeout (QUIC)

Use the --idle-timeout flag to specify a custom QUIC idle timeout (duration).

# Listen with custom QUIC idle timeout (e.g., 2 minutes)
./qcat listen -l :8000 --idle-timeout 2m

Connect mode (client)

# Connect to a QUIC server
./qcat connect -c example.com:8000

# Connect using TCP
./qcat connect -c example.com:8000 -p tcp

# Connect using UDP
./qcat connect -c example.com:8000 -p udp

Verbose Mode

Add -v flag for verbose output:

./qcat listen -l :8000 -v

Learning Network Protocols

This tool is primarily designed for learning purposes. You can use Wireshark to capture and analyze packets while QCat is running to learn about:

1. QUIC protocol handshake and packet structure
2. Differences between TCP and UDP packets
3. Network packet analysis
4. Connection establishment and termination

License

MIT