Masscan

What it does

Masscan is an extremely fast port scanner that can sweep large IP ranges by transmitting packets asynchronously. It's typically used to find open ports across wide external ranges before deeper tooling runs.

Common use cases

• •Scan entire ASN ranges for open ports during the external reconnaissance phase.
• •Identify common web ports across a /8 network in minutes for red-team target selection.
• •Probe large cloud-hosted IP pools to find exposed management interfaces and databases.

Key features

• •Transmits packets asynchronously to scan millions of IPs per second.
• •Supports arbitrary TCP and UDP port ranges across massive CIDR blocks.
• •Outputs results in JSON, CSV, Greppable, and binary formats.
• •Bypasses rate limits through randomized transmission timing and IP rotation.

Source