Once you’ve identified open ports with Nmap, the next step is enumeration – pulling as much detail as possible from the services you’ve found. And if there’s one protocol that’s an absolute goldmine for enumeration, it’s SMB (Server Message Block).

What is SMB?

SMB is a network protocol used primarily by Windows systems for file sharing, printer access, and inter-process communication. It typically runs on port 445 (and historically on port 139 alongside NetBIOS). If you see port 445 open on a target, you’re looking at a Windows machine – and there’s a lot you can learn from it.

NetBIOS Scanning with nbtscan

NetBIOS (Network Basic Input/Output System) is an older protocol that works alongside SMB. You can use nbtscan to quickly identify Windows machines on a network:

nbtscan 10.0.6.200-254

Part of the free Intro to Cyber course by Cover6 Solutions.