nslookup an entire subnet

subnet-scan.sh

#!/bin/bash
## nslookup an entire subnet

## It's possible to add more networks separated with space

if [ ! $1 ]; then
    echo "Missing parameter"
    echo "Usage: To scan 192.168.1.0/24, type:"
    echo "subnet-scan 1"
    exit 1
else
    NETS=192.168.$1  ## edit this line to match the scanned network
    IPRange="1 254"
    for NET in $NETS; do
        for n in $(seq $IPRange); do
            ADDR=${NET}.${n}
            DOM=$(nslookup ${ADDR} | awk -F "=" '{ print $2 }'|sed 's/^[ t]*//' | sed '/^$/d' | sed 's/.$//')
            if [ -n "$DOM" ]; then
                echo "$ADDR, $DOM"
            fi
        done
     done
fi
exit 0