discover all IPs connected in our network, use lan ip of default gateway
nmap -sP $( ip route | grep '^default' | egrep -o '([0-9]{1,3}\.){3}' )0/24 | awk '/^Nmap.*[0-9]$/{print $NF}' | sort -n -t . -k 4
get information from hosts through windows sharing
nmap -script smb-os-discovery -p 445 -open 192.168.0.0/24
show hosts with port 631 open
nmap 192.168.0.0/24 -p 631 -open | awk '/)$/ {print $NF}'
Limits two simultaneous connections on port 80 to each host connected to the network
nmap -sP 192.168.0.0/24 | egrep -o '([0-9]{1,3}\.){3}[0-9]{1,3}' | sort -n -t . -k 4 | xargs -I% iptables -A INPUT -s % -p tcp --dport 80 -m connlimit --connlimit-above 2 -j DROP
