get all Google ipv4/6 subnets for a iptables firewall for example

google has added 2 more netblocks...

for NETBLOCK in $(echo _netblocks.google.com _netblocks2.google.com _netblocks3.google.com); do nslookup -q=TXT $NETBLOCK ; done | tr " " "\n" | grep ^ip[46]: | cut -d: -f2- | sort