Nmap
What it is
Nmap is a free, open-source utility for discovering networks and auditing security. It sends raw IP packets to identify active hosts, services and versions, operating systems, and packet filters or firewalls. Scanning options include TCP and UDP ports, operating-system and version detection, and ping sweeps. Network administrators can use it to build inventories, schedule service upgrades, and monitor host or service uptime. The Nmap Scripting Engine runs bundled or user-written scripts in parallel for tasks such as discovery and vulnerability checks. The suite includes Zenmap, a graphical interface and results viewer; Ncat for data transfer and debugging; Ndiff for comparing scan results; and Nping for packet generation and response analysis. Most scan types require privileged access to send and receive raw packets, although unprivileged users can run connect and FTP bounce scans. Nmap is not a comprehensive vulnerability scanner. End-user use is free, but redistribution inside commercial products requires a separate OEM license. The free version has no warranty and is supported by a community.
For and against
For
- Scans TCP and UDP ports and detects operating systems.
- Scripting engine runs bundled or user-written scripts in parallel.
- Suite includes GUI, data-transfer, comparison, and packet tools.
- Free for end users.
- Source code is available for inspection and security auditing.
Against
- Most port-scan types require privileged access.
- It is not a comprehensive vulnerability scanner.
- Commercial redistribution requires a separate OEM license.
- Free version has no warranty.
The verdict
Nmap provides a broad set of network discovery and administration tools, including scripting and scan-result utilities. It is free for end users, but commercial product redistribution requires an OEM license and it does not replace a comprehensive vulnerability scanner.
Who it suits
Nmap suits network administrators who need host, service, and port discovery, inventory, or uptime monitoring. It can also suit users who want scripting and scan-result comparison tools, provided they understand its privilege requirements and scope.
Plans and prices
Nmap free end-user license
Free use by end users · does not allow redistribution within commercial software or hardware products
Read 29 Sep 2026 · nmap.org
Nmap OEM Small/Startup Company Redistribution License (quarterly term)
All company products · includes maintenance · same small/startup company eligibility
Read 29 Sep 2026 · nmap.org
Nmap OEM Mid-Sized Company Redistribution License (quarterly term)
All company products · includes maintenance · same mid-sized company eligibility
Read 29 Sep 2026 · nmap.org
Nmap OEM Enterprise Redistribution License (quarterly term)
Redistribution in a product line or category · includes maintenance
Read 29 Sep 2026 · nmap.org
Nmap OEM Small/Startup Company Redistribution License (perpetual)
All company products · eligibility: 50 or fewer employees and no more than US$10 million revenue
Read 29 Sep 2026 · nmap.org
Nmap OEM Mid-Sized Company Redistribution License (perpetual)
All company products · eligibility: 500 or fewer employees, revenue under US$200 million, and if publicly traded market capitalization under $1 billion
Read 29 Sep 2026 · nmap.org
Nmap OEM Enterprise Redistribution License (perpetual)
Redistribution in a product line or category · no per-seat royalties
Read 29 Sep 2026 · nmap.org
On the record
- Discovery
- It uses raw IP packets to identify available hosts, services and versions, operating systems, and packet filters or firewalls.nmap.org · read 29 Sep 2026
- Included tools
- The Nmap suite includes the Zenmap GUI and results viewer, Ncat for data transfer and debugging, Ndiff for comparing scan results, and Nping for packet generation and response analysis.nmap.org · read 29 Sep 2026
- Integrations
- For OEM integration, the project recommends running Nmap and parsing its XML-formatted output, and also permits other approaches such as parsing normal output or processing its data files.nmap.org · read 29 Sep 2026
- Network administration
- The project describes network inventory, service upgrade scheduling, and host or service uptime monitoring as routine uses.nmap.org · read 29 Sep 2026
- Notable limitation
- The project says Nmap is not a comprehensive vulnerability scanner, although NSE can perform vulnerability checks.nmap.org · read 29 Sep 2026
- OEM trial and refund
- Perpetual OEM licenses include a six-month period to cancel for a full refund, while the quarterly term license can be terminated for a full refund within its first 30 days.nmap.org · read 29 Sep 2026
- Privileges
- Most port scan types require privileged access to send and receive raw packets; unprivileged users can execute connect and FTP bounce scans.nmap.org · read 29 Sep 2026
- Purpose
- Nmap is a free and open-source utility for network discovery and security auditing.nmap.org · read 29 Sep 2026
- Scanning
- Nmap supports TCP and UDP port scanning, OS detection, version detection, and ping sweeps.nmap.org · read 29 Sep 2026
- Scripting
- The Nmap Scripting Engine runs user-written or bundled scripts in parallel to automate networking tasks, including discovery and vulnerability checks.nmap.org · read 29 Sep 2026
- Security and licensing
- The source code is provided so users can inspect what the program does and audit it for security holes; commercial product redistribution requires a separate OEM license.nmap.org · read 29 Sep 2026
- Support
- The free version has no warranty and is supported by a community, while active OEM maintenance subscriptions include commercial technical support.nmap.org · read 29 Sep 2026
