#!/bin/bash
# Bulk DNS Lookup 
# Credit: https://gist.github.com/chrisdavidmiles/5aa1b3c7194bde4c7aa34895c1e497d6
# Generates a CSV of DNS lookups from a list of domains.

## Command to format your blacklist properly
## cat blacklist.txt | grep -v '^#' | tr -s '\n' '\n' | grep -Ev "^$" | grep -o '^[^#]*' > tmp_blacklist

# File name/path of domain list:
domain_list='blacklist.txt' # One FQDN per line in file.
#
# IP address of the nameserver used for lookups:
ns_ip='1.0.0.1' # Is using Cloudflare's 1.1.1.1.
#
# Seconds to wait between lookups:
loop_wait='1' # Is set to 1 second.

echo "Domain name, IP Address, IP PTR, IP NetName (WHOIS)"; # Start CSV
echo > invalid.txt
for domain in `cat $domain_list | grep -v '^#' | tr -s '\n' '\n' | grep -Ev "^$" | grep -o '^[^#]*' ` # Start looping through domains

do
    ip=`dig @$ns_ip +short $domain |tail -n1`; # IP address lookup
    if [ ! -n "$ip" ] # If the IP is null (expired or invalid domain)
        then # Then
            echo "$domain,No DNS,," >> invalid.txt; # Write "No DNS" in the IP column
        else # And if an IP is found perform a PTR and NetName lookup
            echo -en "$domain,$ip,"`dig @$ns_ip +short -x $ip |xargs`",";
            whois $ip |grep -i 'netname' |awk '{print $NF}'|xargs;
    fi
    sleep $loop_wait # Pause before the next lookup to avoid flooding NS
done;