enum4linux-ng
enum4linux-ng -A <target-ip>
SMB/NetBIOS enumeration tool that automates smbclient, rpcclient, and nmblookup.
When you lack credentials and want to test null sessions, or when you have credentials and want quick SMB/RPC enumeration. enum4linux-ng is the modern version of enum4linux, with better authentication handling.
If security policy blocks null sessions and you have no credentials. Also, if you only need a specific module (e.g., listing users), it's better to use the direct command.