My Best Experiences with NMAP

 Command 1: nmap -sS -A -O -sS -sU <Target IP>
               PORT STATE SERVICE VERSION
                    21/tcp open ftp vsftpd 2.0.4
                    |_ftp-anon: Anonymous FTP login allowed (FTP code 230)
           Aggressive OS guesses
               Network Distance
               Host script results
               Tracroute
      **Above command consumes little more time :) 

 Command 2: nmap -sS <Target IP> -p21,23,80,139,445 --reason
       reason --> specifies decision on port state

 Command 3: nmap -p445 --script=smb-os-discovery <Target IP>

 Command 4: nmap --osscan-limit -n -vvv -PN --scan-delay 1s -A

Will discuss more in coming post's....