useful nmap scans

enumerate and find as much information of the top 1000 ports (recommended first scan):
$ nmap --top-ports 1000 -T4 -sC
network sweeping:
$ nmap -sn
scan for the top 20 TCP ports and save output in a file:
$ nmap -sT -A --top-ports=20 -oG top-port-sweep.txt
banner grabbing, service ennumeration:
$ nmap -sV -sT
OS identifying:
$ nmap -O
attempt to connect to the SMB service:
$ nmap --script smb-os-discovery.nse
DNS zone transfer NSE script
$ nmap --script=dns-zone-transfer -p 53

Written on August 9, 2017