This is the fastest Internet port scanner. It can scan the entire Internet in under 6 minutes, transmitting 10 million packets per second.

It produces results similar to nmap, the most famous port scanner. Internally, it operates more like scanrand, unicornscan, and ZMap, using asynchronous transmission. The major difference is that it's faster than these other scanners. In addition, it's more flexible, allowing arbitrary address ranges and port ranges.

NOTE: masscan uses a custom TCP/IP stack. Anything other than simple port scans will cause conflict with the local TCP/IP stack. This means you need to either use the -S option to use a separate IP address, or configure your operating system to firewall the ports that masscan uses.

This tool is free, but consider funding it here: 1MASSCANaHUiyTtR3bJ2sLGuMw5kDBaj4T

Building

On Debian/Ubuntu, it goes something like this:

$ sudo apt-get install git gcc make libpcap-dev
$ git clone https://github.com/robertdavidgraham/masscan
$ cd masscan
$ make

This puts the program in the masscan/bin subdirectory. You'll have to manually copy it to something like /usr/local/bin if you want to install it elsewhere on the system.

The source consists of a lot of small files, so building goes a lot faster by using the multi-threaded build:

$ make -j

While Linux is the primary target platform, the code runs well on many other systems. Here's some additional build info:

• Windows w/ Visual Studio: use the VS10 project
• Windows w/ MingGW: just type make
• Windows w/ cygwin: won't work
• Mac OS X /w XCode: use the XCode4 project
• Mac OS X /w cmdline: just type make
• FreeBSD: type gmake
• other: I don't know, don't care