spf.postini.com has no NS records.
NS records for this zone are defined at postini.com.
NS records for this zone are defined at postini.com.
Question and response
Question
dig spf.postini.com. NS
Answer
The response has no answer records.
Authority
postini.com. 60 SOA ns1.google.com. postini-hostmaster.google.com. 881325283 7200 3600 3600000 600
Additional
. 0 OPT ; payload 512, xrcode 0, version 0, flags 0