Question and response
Question
dig _netblocks.google.com. TXT
Answer
_netblocks.google.com. 300 TXT "v=spf1 ip4:74.125.0.0/16 ip4:209.85.128.0/17 ~all"
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 512, xrcode 0, version 0, flags 0