flowguard

FlowGuard Pro

FlowGuard Pro is an advanced, terminal-based Network Traffic Controller built with Go (Golang). It is designed to give you complete visibility and control over your Local Area Network (LAN).

Inspired by legendary tools like NetCut and SelfishNet, FlowGuard Pro modernizes the concept by introducing Dual-Stack Support (IPv4 & IPv6), cross-platform compatibility, and a beautiful TUI (Terminal User Interface).

⚠️ LEGAL DISCLAIMER

This tool is developed for EDUCATIONAL, RESEARCH, and NETWORK ADMINISTRATION PURPOSES ONLY. Using this tool against networks or devices without explicit permission from the owner is ILLEGAL and may violate local and international laws. The author assumes no liability for misuse.

Key Features

Dual-Stack Network Control

• IPv4 Dominance: Uses aggressive ARP Spoofing to redirect traffic through your machine (MITM).
• IPv6 Neutralization (New): Uses ICMPv6 Neighbor Advertisement Spoofing (DAD Attack) to force targets to drop their IPv6 connections, preventing them from bypassing blocks via modern protocols.

High-Performance Engine

• Burst Mode: Instantly cuts off connections by sending a barrage of spoofed packets when a target is blocked (eliminates the "second block failure" bug).
• LAN Optimization: Smart BPF Filtering prevents packet loopbacks and CPU saturation, ensuring the attacker's internet remains stable even on Gigabit Ethernet connections.

Self-Protection

• Gateway Locking: Automatically locks the Gateway's MAC address in your system's ARP table (netsh on Windows, ip neigh on Linux) to prevent self-poisoning.

Real-Time Management

• Live Speedometer: Monitor real-time Upload/Download speeds of any target.
• Bandwidth Limiter: Throttle connection speeds (e.g., limit a device to 50KB/s).
• Device Alias: Rename devices (e.g., "My Phone", "Office PC") with persistent saving.

Requirements

Windows

• OS: Windows 10 / 11.
• Driver: Npcap (Install with "Install Npcap in WinPcap API-compatible Mode" checked).
• Privileges: Must run as Administrator.

Linux (Debian/Ubuntu/Alpine)

• Library: libpcap-dev.
• Privileges: Must run with sudo.

Installation & Usage

1. Clone Repository

git clone [https://github.com/bugkey24/flowguard.git](https://github.com/bugkey24/flowguard.git)
cd flowguard

2. Install Dependencies

go mod tidy

3. Run the Application

Windows (PowerShell/CMD as Admin):

go run main.go

Linux (Terminal):

# Install libpcap first (Debian/Ubuntu)
sudo apt update && sudo apt install libpcap-dev

# Run FlowGuard
sudo go run main.go

Controls & Shortcuts

The interface is navigable entirely via keyboard.

Technical Details

FlowGuard Pro operates at Layer 2 (Data Link) and Layer 3 (Network) of the OSI Model.

1. Scanner: Uses pcap to listen for ARP traffic and passively inspects IPv6 packets to discover dual-stack devices.

2. IPv4 Attack (ARP): Continually sends forged ARP replies to the Target (saying "I am the Router") and the Router (saying "I am the Target").

3. IPv6 Attack (ICMPv6): Sends forged Neighbor Advertisements claiming that the Target's IPv6 address belongs to the Attacker's MAC. This triggers a "Duplicate Address Detection" (DAD) conflict, causing the target OS to disable IPv6 or drop the connection.

4. Forwarding Engine:

   • Only forwards packets belonging to tracked targets.
   • Applies Token Bucket algorithms for Bandwidth Limiting.
   • Drops packets instantly if "Block" is active.

Troubleshooting

1. "Internet on my laptop (Attacker) dies when using LAN!" FlowGuard uses strict BPF filters (not dst host [MyIP]) to prevent your own high-speed download traffic from clogging the packet capture engine. Ensure you are using the latest version of the code.

2. "Target is not blocked on YouTube/Netflix." Ensure the target shows (v6) next to its name. If not, wait a few seconds for FlowGuard to detect the IPv6 address. FlowGuard automatically attacks both protocols to ensure total blockage.

3. "I don't see any devices."

   • Windows: Ensure you selected the correct Network Adapter (check IP address).
   • Linux: Ensure you are running with sudo.

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

1. Fork the Project
2. Create your Feature Branch (git checkout -b feature/AmazingFeature)
3. Commit your Changes (git commit -m 'Add some AmazingFeature')
4. Push to the Branch (git push origin feature/AmazingFeature) Open a Pull Request

License

Distributed under the MIT License. See LICENSE for more information.