QUESTION :
I scanned my home network using nmap 192.168.178.* and 192.168.178.0-255 but it doesn’t show the IP of my PC. Then when I scan only my PC using -Pn it finds it. So why is my PC hidden?
And even after finding it with -Pn why it doesn’t show real info about my OS, it shows only like Windows, Windows 98, while it is Windows 10.
ANSWER :
I believe by default nmap does a ping scan of the target IP addresses. If your host doesn’t respond to pings — perhaps because it is running a local software firewall that blocks it in order to be less findable on the network — then nmap will not be able to find it with pings.
When OS fingerprinting fails, it is usually because nmap could not get the target host to respond to much of anything, so nmap was unable to learn anything meaningful.
If you have a firewall enabled on that target host, then it seems like it is doing its job.