: Uses ARP (Address Resolution Protocol) spoofing to intercept traffic between the router and other devices. Extreme Simplicity

Mac Spoofing. See how many devices are connected to your network. Check the IP's and Mac addresses of the devices on your network.

The host then applies user-defined limits on upload/download speeds or drops packets entirely ("Blocking") before forwarding legitimate traffic to the real router. 4. Features and Limitations Key Features Real-time Monitoring:

Today, the term "selfish" in networking has evolved. Ethical hacking emphasizes collaboration. However, the red team mindset—where you assume everyone on the network is adversarial—was popularized by tools like SelfishNet. It taught us that on a shared medium (Wi-Fi), trust is a vulnerability.

By 2008, most antivirus suites (Norton, McAfee, Kaspersky) began flagging SelfishNet as a "HackTool:ARP" or "Riskware." It wasn't a virus, but it was a tool for malicious activity. Users had to disable real-time protection to run it—a terrible idea for any beta software.

: As a "v0.1 Beta" project, it is prone to crashing, especially on modern versions like Windows 10 and 11. Legacy Requirements : It relies on the older

SelfishNet is a specialized Windows application designed to put the power of network administration into the hands of a single user on a shared connection. Its name perfectly encapsulates its function: it allows you to prioritize your own internet experience, often at the expense of others on the same network.

The original v0.1 beta has long since been abandoned. However, the concept proved popular, leading to other developers creating their own versions. The most notable is SelfishNet V3, written in C#, which is currently in development as of late 2025 and early 2026. You can find its source code and the latest releases on GitHub under the user abelmez . This version adds features like MAC Spoofing and a more user-friendly installer, providing a modern take on the classic tool.

To limit speed, click inside the or Upload column for that device and type a maximum speed value in kilobytes per second (KB/s).

Instantly disconnect specific devices from the internet.

driver, which is no longer maintained and can be difficult to set up on newer systems. Security Risks

For critical network infrastructure (like servers and routers), administrators can configure static ARP entries. This manually maps IP addresses to MAC addresses, preventing the device from accepting spoofed ARP replies for those specific IPs. However, this is impractical for large or dynamic networks.

This is SelfishNet's signature feature. For any discovered device, you can input a maximum number into the "Download Cap" and "Upload Cap" boxes. Once set, the user's speed will be immediately throttled to that exact limit. You can allocate just enough bandwidth for someone to check emails and browse social media without letting their video calls or downloads disrupt your own connection.

Users can manually input specific speed limits (in KB/s) for any device on the network to prevent them from consuming too much data.