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Masscan
What it is
Masscan is free command-line software for scanning TCP ports across many machines and wide address ranges. The project says it can transmit 10 million packets per second from a single machine. It supports asynchronous transmission and arbitrary port and address ranges, and can scan IPv4 and IPv6 together. Banner checks cover services including FTP, HTTP, IMAP4, memcached, POP3, SMTP, SSH, SSL, SMBv1, SMBv2, Telnet, RDP, and VNC. Results can be saved as XML, binary, grepable, JSON, or list output. Its usage and output are designed to be familiar to Nmap users, with some compatible options. Masscan runs on Linux, macOS, and Windows, and is available for self-hosting. It is free software under the GNU Affero General Public License version 3; the license notice states that it comes with no warranty. The project describes it as tuned for wide-range scanning of many machines, rather than intensive scanning of a single machine or small range. Users must specify ports, and targets must be IP addresses or simple ranges rather than DNS names. The README warns that its custom TCP/IP stack can conflict with the local stack.
For and against
For
- Free software under the GNU Affero General Public License v3.
- Scans IPv4 and IPv6 together.
- Supports banner checks for a broad set of services.
- Exports XML, binary, grepable, JSON, and list output.
- Available for Linux, macOS, and Windows.
Against
- Users must specify ports.
- Targets must be IP addresses or simple ranges, not DNS names.
- Its custom TCP/IP stack can conflict with the local stack.
- The license notice states that the software has no warranty.
The verdict
Masscan is built for broad, high-speed TCP port scanning, with multiple output formats and service banner checks. Its target requirements and possible TCP/IP stack conflict are important operational considerations.
Who it suits
Masscan suits users who need to scan many machines across broad IP ranges. Its command-line workflow and target requirements make it a tool for users comfortable specifying ports and IP addresses or ranges.
Plans and prices
Free
Internet-scale scanning · arbitrary IP and port ranges · command-line use
Read 15 Oct 2026 · github.com
Masscan
Free software under the GNU Affero General Public License v3
Read 5 Oct 2026 · github.com
On the record
- Address and port ranges
- Masscan accepts arbitrary IP address ranges and port ranges, including IPv4 and IPv6 examples.github.com · read 15 Oct 2026
- Asynchronous scanning
- It sends SYN packets asynchronously and uses a design comparable to scanrand, Unicornscan and ZMap.github.com · read 15 Oct 2026
- Banner checks
- Banner checking is supported for FTP, HTTP, IMAP4, memcached, POP3, SMTP, SSH, SSL, SMBv1, SMBv2, Telnet, RDP, and VNC.github.com · read 5 Oct 2026
- Banner-grab hazard
- The host stack can send reset packets after SYN-ACK responses, terminating connections before Masscan captures banners.github.com · read 15 Oct 2026
- Banner protocols
- Banner checking is documented for FTP, HTTP, IMAP4, memcached, POP3, SMTP, SSH, SSL, SMBv1, SMBv2, Telnet, RDP and VNC.github.com · read 15 Oct 2026
- Build requirements
- The basic Linux build requires Git, Make and a C compiler such as GCC or Clang, with no other major dependencies described.github.com · read 15 Oct 2026
- Compatibility
- Masscan's usage and output are designed to be familiar to Nmap users, with some Nmap-compatible options.github.com · read 5 Oct 2026
- Configuration export
- The --echo option prints the current configuration so it can be saved and reused as an input configuration file.github.com · read 15 Oct 2026
- Copyright date
- The licence notice identifies copyright as 2013 Robert David Graham.github.com · read 15 Oct 2026
- Custom TCP/IP stack
- Masscan includes its own ad hoc TCP/IP stack, which can conflict with the host operating system stack.github.com · read 15 Oct 2026
- Distributed scans
- The Debian manual documents --shard for dividing a scan across machines and resume indexes for assigning chunks to workers such as Amazon EC2 instances.manpages.debian.org · read 15 Oct 2026
- High-speed integration
- PF_RING ZC can be used beyond about two million packets per second with a compatible Intel 10-gigabit adapter and drivers.github.com · read 15 Oct 2026
- Integrations
- The project describes PF_RING DNA support for high-speed packet transmission and says Masscan can use PF_RING ZC when the adapter name indicates it.github.com · read 5 Oct 2026
- Intended users
- The README describes Masscan as tuned for scanning many machines across wide ranges, while Nmap is described as designed for intensive scanning of a single machine or small range.github.com · read 5 Oct 2026
- IPv6
- IPv4 and IPv6 can be scanned together, without a separate IPv6 mode.github.com · read 5 Oct 2026
- Kali package
- Kali lists Masscan as a TCP port scanner installable with sudo apt install masscan, with an installed size of about 516 KB and libc6 and libpcap dependencies.kali.org · read 15 Oct 2026
- Licence
- Masscan is released under the GNU Affero General Public License version 3.github.com · read 15 Oct 2026
- License
- Masscan is free software under the GNU Affero General Public License version 3, with no warranty stated in the license notice.github.com · read 5 Oct 2026
