fscan

Fscan is a one-command internal network scanner for security testing. Point it at an IP range and it does host discovery, port and service scanning, web and CMS fingerprinting, weak-credential brute-forcing across dozens of services, and checks for known vulnerabilities like MS17-010. It is the kind of tool a red teamer reaches for to map and probe an internal network fast. Written in Go, MIT licensed, free.

Running it is genuinely one command: `./fscan -h 192.168.1.1/24` and it goes. A single static Go binary, no dependencies, cross-platform, with an optional web UI. That simplicity is the whole appeal; there is nothing to install or configure before you are scanning.

For anyone doing authorized penetration testing or defending their own network, this is a fast, capable recon tool at zero cost. Solo testers and security teams use it the same way. There is no paid tier and no team story; it is a CLI you run against targets you are allowed to test.

The catch is that this is a dual-use offensive tool, and the responsibility is entirely yours. Fscan includes brute-forcing, credential extraction, and exploitation modules that are legal on networks you own or are contracted to test, and a crime everywhere else. It also lights up every IDS in the building. Use it inside a real engagement scope, not because it is easy to point at something.