[SOLVED] Why use nmap options -Pn or -sT

walterbyrd · 03-29-2020, 08:16 PM

I have looked up those options in the man pages, and in the manual. I know what they are supposed to do, but I don't understand what good they would do.

-Pn: Treat all hosts as online -- skip host discovery

Why treat an offline host as through it were online? In fact, how is that even possible?

-sT: Connect scan

I'm not even exactly sure what this does.

michaelk · 03-29-2020, 09:23 PM

In a nutshell host discovery is basically sending a ping command and receiving a reply. However, a host's can be configured to block or drop ICMP messages and therefore nmap assumes it is offline. If that is the case and you know the host is actually online you can use -Pn to bypass sending a ping.

A TCP connect scan is explained in the nmap documentation.
https://nmap.org/book/scan-methods-connect-scan.html