Script to update ipset list "google-ips" with Google IP range

google_iprange_update.sh

#!/usr/bin/env bash

ipset_name="google-ips"
ipset_name_tmp="google-ips-tmp"
iptables_name="nginx-google-whitelist"
port="7654"

#########################################################

ipset -q create "$ipset_name" nethash
iptables -N "$iptables_name" 2> /dev/null

if [ $? -eq 0 ]; then
  iptables -A INPUT -p tcp -m tcp --dport $port -j "$iptables_name"
  iptables -A "$iptables_name" -m set ! --match-set "$ipset_name" src -j DROP
fi

ipset -q destroy "$ipset_name_tmp"
ipset create "$ipset_name_tmp" nethash

# _netblocks2 is ipv6
subdomains="_netblocks _netblocks3"
for subdomain in $subdomains
do
    response=$(nslookup -q=TXT $subdomain.google.com 8.8.8.8)
    ips=$(echo "$response" | egrep -o '\<ip[46]:[^ ]+' | cut -c 5-)

    for ip in $ips
    do
      ipset add "$ipset_name_tmp" "$ip"
    done
done

ipset swap "$ipset_name" "$ipset_name_tmp"
ipset destroy "$ipset_name_tmp"