Generates a CSV of DNS lookups from a list of domains

bulk_dns_lookup.sh

#!/bin/bash
# Bulk DNS Lookup
# Generates a CSV of DNS lookups from a list of domains.
#
# File name/path of domain list:
domain_list='domains.txt' # One FQDN per line in file.
#
# IP address of the nameserver used for lookups:
ns1_ip='1.1.1.1' # Cloudflare
ns2_ip='9.9.9.9' # Quad9
ns3_ip='1.1.1.2' # Cloudflare Malware
ns4_ip='103.247.36.36' # DNS Filter
ns5_ip='208.67.222.222' # OpenDNS / Cisco Umbrella
#
# Seconds to wait between lookups:
loop_wait='1' # Is set to 1 second.

echo "Domain name, $ns1_ip,$ns2_ip,$ns3_ip,$ns4_ip,$ns5_ip "; # Start CSV
for domain in `cat $domain_list` # Start looping through domains
do
    ip1=`dig @$ns1_ip +short $domain |tail -n1`; # IP address lookup DNS Server1
    ip2=`dig @$ns2_ip +short $domain |tail -n1`; # IP address lookup DNS server2
    ip3=`dig @$ns3_ip +short $domain |tail -n1`; # IP address lookup DNS server3
    ip4=`dig @$ns4_ip +short $domain |tail -n1`; # IP address lookup DNS server4
    ip5=`dig @$ns5_ip +short $domain |tail -n1`; # IP address lookup DNS server5
            echo -en "$domain,$ip1,$ip2,$ip3,$ip4,$ip5\n";
#    sleep $loop_wait # Pause before the next lookup to avoid flooding NS
done;