masscan
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Internet-scale port scanner that transmits up to 10 million packets per second using an asynchronous, custom TCPTCPA network protocol that delivers a reliable, ordered stream of bytes between two endpoints. It detects lost data and retransmits it./IP stack.
Summary
masscan is an open-source, free command-line port scanner built for Internet-scale reconnaissance, able to sweep the entire IPv4 address space in under five minutes by transmitting up to 10 million packets per second from a single machine. It uses its own ad hoc TCP/IP stack rather than the operating system's, which gives it that speed but means source IP or port configuration is needed alongside firewall rules to avoid conflicts. Its README describes usage similar to nmap and places its asynchronous scanning approach alongside tools like scanrand, unicornscan, and ZMap, while allowing more flexible address and port ranges. It suits network engineers and red teamers doing large-scale recon rather than deep single-host analysis, and with 91 contributors and commits in the past year, the project remains actively maintained since its 2013 start.
Internet-scale port scanner that transmits up to 10 million packets per second using an asynchronous, custom TCP/IP stack.
How masscan helps
Which hosts on this network segment are actually alive right now?
sweeps the address range asynchronously and lists every host that responded, without waiting on a full connection to each one before moving to the next
Which ports are open across an entire subnet or address block?
fires packets across the whole range in parallel and reports back every host and port pair that answered, at a scale a connect-based scan can't cover in the same time
Can this whole allocation be scanned before the next change window closes?
drives transmission rates up to millions of packets per second from one machine, so a range that would take hours with a slower scanner finishes in minutes
What does an Internet-wide sweep of one port look like across every reachable address?
is built to walk the entire IPv4 space against a chosen port set and exclusion list, producing a single pass of results instead of many smaller scans stitched together
How do I capture the results of a huge scan for later analysis?
can write the full run to a structured file as it goes, so a scan spanning millions of addresses still leaves a record to parse afterward instead of only console output
Can I hand off a large recurring scan so it runs the same way every time?
takes its targets, ports and rate from a saved configuration file, so the same sweep can be repeated without re-typing every option
Languages
Command line
No command matches.
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Values are placeholders taken from each option’s declared default. Nothing is executed here — the output shown is a recording of a run that already happened.
Score card
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Shipping velocity releases a month, last 12 months
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Documentation quality release-notes rubric, 0–100
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Breaking-change discipline how rarely a release breaks users, and notice given
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Maintenance risk quiet time against its own cadence, maintainers
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Innovation & surface new capabilities, API and MCP surface
- Community health
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Contributor trend distinct committers, this year against last
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Maintainer concentration bus factor now against a year ago
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Issue backlog trend issues closed per issue opened, 12 months
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Responsiveness median time to a maintainer’s first reply
Nine scores for masscan, each built from the releases, notes and API history this site tracks — and, on Researcher and Business, where it stands among every measured tool in its category and how that has moved.
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Blank means never measured; nothing here is a filled-in zero.
Peer standings are included with Researcher and Business. See how this tool ranks against its competitors, using data we don't publish anywhere else.
See plans →Each score is 0–100 on a published rubric, derived from data this site already shows. A dimension we cannot measure says so — it is never scored 0 and never enters a rank.
How this is scored
- Shipping velocity — releases a month over the last 12 months, on a log scale where 16 a month scores 100. Needs 3 releases in the window.
- Documentation quality — the release-notes rubric published on the analytics page, unchanged.
- Breaking-change discipline — the share of releases carrying a breaking change (none scores 100, half or more scores 0). Only projects that label breaking changes are measured: a clean record cannot be told from an unlabelled one.
- Maintenance risk — quiet time measured against the tool's own release cadence (quiet longer than 90 days and three typical gaps scores 0), plus the number of active maintainers and whether contributors are growing, where known. Higher is lower risk.
- Innovation & surface — new capabilities in the feature ledger this year, API and MCP operations added, and the share of commits that are features: the mean of whichever we hold.
- Community health (open-source tools only) — each is a direction, not a size: contributors this year against last, the bus factor now against a year ago, and issues closed per issue opened, where steady scores 50, doubled 100 and halved 0; plus the median time to a maintainer's first reply (an hour scores about 100, a month or more 0). A commercial card has no repository and carries none of the four.
- Documented delivery (commercial tools) — when a vendor's documented new capabilities have slowed against its own baseline, that counts against the overall standing as heavily as two low dimensions. Steady delivery, or too little history to judge, leaves the standing alone; it is never a sixth score.
- Open-source tools are scored on repository signals; commercial tools on their published changelog. Ranks compare tools within one category and one profile and need at least five measured peers; the overall standing needs three ranked dimensions. Best-in-breed or consolidator is a shape, not a quality, and is never scored.
Release-note detail over time
See how much detail masscan puts in its release notes, quarter by quarter, and compare it with tracked tools in the same category. This history uses up to ten retained, reviewed notes per tool; sparse or blank older quarters may reflect that limit.
Checking release-note history…
Releases
Nothing shipped since we started watching. Releases and docs updates land here as they happen.
Project health
Issue, contributor and maintainer activity in robertdavidgraham/masscan, 2023-10 – 2026-09, as of 2026-09-25. Twelve-month figures first; the trend lines run the whole window.
- Contributors 4 −2 vs prior 12 months
- Maintainers 1 +1 joined · −0 left, last 12 months
- Bus factor 1 committers behind half the commits
- Community-filed 100% of issues opened, last 12 months
- Median time to close 274 days first maintainer reply 8 days
- Open backlog 383 of 593 issues ever filed
- Issues opened / month 0 · 0 communitymaintainers
- Open backlog 383
- Contributors / month 0
- Commits / month 0
- Stars 26,013
- other 100%
Counts from the project's public repository and git history; no individuals are identified. Maintainers are the committers covering 80% of the last year's commits. how we measure this
Articles
3 articles · updated Nov 4, 2026Where masscan turns up in what others publish: how-tos, attack reports that name it, and incident write-ups. A row says why it is here and quotes where the article names it; the link goes to the publisher.
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Ransomware incidents in Japan in the first half of 2026: Investigation of The Gentlemen’s infrastructure and evidence of Qilin's AI use
The actor then repeatedly installs and configures reconnaissance tools such as nmap and masscan, along with BloodHound, NetExec, Responder, and Impacket for targeting AD environments, all within the same command history.
1 more quote
They appear to have used Masscan and Nmap to assess publicly exposed hosts, VPN-related ports, web services, SMB, and other active services in order to understand the external and internal network structure.
Libraries its release ships
What its latest release locks, checked against known advisories.None of its release's images build from a lockfile we can read.
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