masscan

Name: masscan
Availability: InStock
Author: Dave

Scan large IP ranges for open TCP ports using asynchronous SYN packets.

15|1|Updated Feb 12, 2026

Search Tags:#vulnerability assessment #reconnaissance #masscan #port scanner #network sweep #tcp syn

Ready to run

npx skills add https://github.com/AeonDave/malskill --skill masscan

💬 Prompt for ChatGPT / Claude Chat▼

Please help me install this Agent Skill.
Skill: masscan
Source: https://github.com/AeonDave/malskill/tree/main/offensive-tools/network/masscan
Command: npx skills add https://github.com/AeonDave/malskill --skill masscan

SYSTEM DOCUMENTATION & REQUIREMENTS

💡 This Skill includes references (resource) components.

What problem does it solve?

This Skill automates the process of identifying open ports across vast network ranges quickly and efficiently, serving as a crucial first step in network reconnaissance.

Core Features & Use Cases

Ultra-fast Port Scanning: Utilizes asynchronous TCP SYN scanning to achieve high speeds.
Wide-Area Network Sweeps: Ideal for scanning entire IPv4 internet ranges or large CIDR blocks.
First-Pass Discovery: Acts as an initial discovery tool before more in-depth scanning with tools like nmap.
Use Case: Quickly identify all hosts with port 445 open across a large corporate network segment.

Quick Start

Use the masscan skill to scan the 10.0.0.0/16 network for port 445 at a rate of 10000 packets per second and save the output to out.gnmap.

Frequently Asked Questions about masscan

High-intent search queries and answers about installing and using this skill.

FAQPage Schema

How do I scan large IP address ranges for open ports quickly?▼

Scanning large IP address ranges quickly requires an asynchronous TCP SYN port scanner. This approach transmits packets efficiently to perform wide-area network sweeps and identify open ports across vast networks in minutes.

What is the best way to perform a network sweep before detailed service analysis?▼

A first-pass network sweep using asynchronous TCP SYN scanning identifies open ports across large CIDR blocks. This initial discovery phase pinpoints active hosts before running in-depth service analysis with tools like nmap.

Can I scan an entire IPv4 internet range for a specific port?▼

Yes, you can scan an entire IPv4 internet range for a specific port. Ultra-fast asynchronous TCP SYN scanning handles massive network sweeps by efficiently transmitting packets to discover open targets.

How do I find all hosts with port 445 open across a corporate network segment?▼

To find hosts with port 445 open across a corporate network segment, perform an asynchronous TCP SYN scan. Specify the target CIDR block, set a packet transmission rate, and save the output to a file for analysis.

Does masscan perform deep service analysis or just port discovery?▼

masscan focuses on ultra-fast port discovery rather than deep service analysis. It serves as an initial first-pass discovery tool to identify open ports, requiring subsequent tools for comprehensive service analysis.

Why use asynchronous TCP SYN scanning instead of other port scanning methods for large networks?▼

Asynchronous TCP SYN scanning is used for large networks because it achieves ultra-fast packet transmission rates. This speed facilitates wide-area network sweeps across vast IP ranges, outperforming standard scanning methods.