Network mapping and IP Packet crafting using Nmap

Type nmap $-$h$,$ you should get the syntax for nmap along with its options.

To send a SYN packet to the computer that hosts Google web service and scan that computer in order to know what UDP$/$TCP ports are open, type nmap $-$sS ${?}^n-v$ option $to$ interactively see what $is$ going $on.(what$ are the open ports$)$

$TCP$ connect scan

$TCPSYN$ scan

$TCP$ FIN scan

$()n$