_spf.ihg.com has no NS records.
NS records for this zone are defined at ihg.com.
NS records for this zone are defined at ihg.com.
Question and response
Question
dig _spf.ihg.com. NS
Answer
The response has no answer records.
Authority
ihg.com. 3600 SOA a1-131.akam.net. hostmaster.akamai.com. 2015045038 86400 7200 2419200 172800
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0