Masscan: A High-Speed Network Port Scanner

Masscan is a powerful and extremely fast network port scanner. It is designed to scan large networks very quickly, making it an invaluable tool for network administrators, security professionals, and researchers. Unlike traditional scanners like Nmap, Masscan can scan the entire IPv4 address space in just a few minutes, depending on the network conditions and the user's hardware.

Understanding Masscan Usage

Masscan's command-line interface is designed to be intuitive, drawing inspiration from tools like Nmap. This allows users familiar with network scanning to quickly adapt to its syntax and capabilities.

Scanning Specific Ports and Networks

To scan a network segment for a specific set of ports, you can use the following syntax. This example demonstrates scanning ports 80 and a range from 8000 to 8100 on the 10.0.0.0/8 network.

# Usage is similar to nmap. To scan a network segment for some ports
masscan -p80,8000-8100 10.0.0.0/8

Scanning the Entire Internet with Exclusions

For more extensive scans, such as scanning the entire IPv4 address space, Masscan offers robust options. The following command scans all ports (0-65535) on the entire internet (0.0.0.0/0), excluding hosts listed in a specified file (`exclude.txt`), and sets a maximum rate of 100,000 packets per second.

# scan the entire Internet excluding exclude.txt
masscan 0.0.0.0/0 -p0-65535 --excludefile exclude.txt --max-rate 100000

Key Features and Benefits

Masscan's primary advantage is its speed. It achieves this by using an asynchronous transmission method, allowing it to send and receive packets independently of each other. This makes it ideal for tasks such as:

• Discovering open ports across vast IP ranges.
• Identifying vulnerable services on a network.
• Performing network inventory and asset management.

Further Resources

For more in-depth information on Masscan's capabilities, advanced usage, and best practices, consult the official documentation and related security resources:

• Masscan GitHub Repository
• Nmap Documentation (for comparative understanding)
• IANA Service Name and Transport Protocol Port Number Registry