Let discuss about NMAP

tq Fallenzero..
effort is everything...
i'll try it 1st...

apit- what exactly do want out of nMAP? I think once you figure that out, you'll learn a lot quicker

that is my gateway info..
is it possibble for hackers to hack to the open port?
how to protect our pc from the attacker?

--Check the below link.

www.iana.org/assignments/port-numbers

It gives you Port Numbers and Services offered by the Port. Look at your Open Ports and see what Services are being offered. Google for your Open Ports/Services and see if there are any exploits currently out there.

Block Ports using a Firewall that you don't want the outside world to see.

Thats a hell of a lot of open ports for a gateway system... however you seem to be scanning it from the LAN side..
scan your system from its public interface and see what you come up with.

if we scan any host, can anybody detect us?
is it legal?