A simple banner grabber which connects to an open TCP port and prints out anything sent by the listening service within five seconds.
The banner will be truncated to fit into a single line, but an extra line may be printed for every increase in the level of verbosity requested on the command line.
How long to wait for a banner. Default: 5s
Which ports to grab. Same syntax as -p option. Use "common" to only grab common text-protocol banners. Default: all ports.
nmap -sV --script=banner <target>
21/tcp open ftp |_ banner: 220 FTP version 1.0\x0D\x0A
License: Same as Nmap--See https://nmap.org/book/man-legal.html