robertdavidgraham/masscan

Health v2 · maintenance only

Adoption not part of the score

25955 stars · 3238 forks observed · 2026-08-28

What it is AI-extracted, prompt v1, taxonomy v1, 2026-08-29, confidence not recorded

Masscan is an Internet-scale TCP port scanner written in C that transmits 10 million SYN packets per second, capable of scanning the entire Internet in under 5 minutes from a single machine. It uses its own ad hoc TCP/IP stack with asynchronous transmission and offers nmap-like usage and output.

Use cases

• scan the entire internet for open ports
• fast port scanning of large network ranges
• find hosts with a specific port open across a subnet
• nmap alternative for mass scanning
• audit exposed services on my network
• scan millions of IPs quickly from one machine

When to choose

• you need to scan huge address ranges or the whole internet at maximum speed
• you want simple SYN port scanning with nmap-like syntax
• you need a dependency-free C tool that runs on Linux, Windows, macOS, and BSD

When to avoid

• you need in-depth scanning of single machines, service version detection, or NSE scripts - use nmap instead
• you cannot configure firewall rules or source IP/port to avoid conflicts with the local TCP/IP stack
• you need a passive or low-noise scan; masscan's packet rate is highly conspicuous

Facets

cli-tool · maturity active

security networking penetration-testing security networking penetration-testing windows bsd cli cross-platform port-scanner tcp-syn-scanning internet-scale-scanning nmap-compatible high-performance raw-packets c command-line linux macos

Member repositories

For agents

markdown · JSON · MCP: product_card(name="robertdavidgraham/masscan")