Handmade Network Scan

Port scanner

#!/bin/bash
host=$1
for port in {1..65535}; do
    timeout .1 bash -c "echo >/dev/tcp/$host/$port" &&
        echo "port $port is open"
done
echo "Done"

Ping scanner with reverse DNS lookup

(1..254) | % {$ip="10.0.40.$_"; Write-output "$IP  $(test-connection -computername "$ip" -quiet -count 1)  $( Resolve-DnsName $ip -ErrorAction Ignore |select -exp NameHost ) "}