mail1168.newsletter.ti.com has no NS records.
NS records for this zone are defined at ti.com.
NS records for this zone are defined at ti.com.
Question and response
Question
dig mail1168.newsletter.ti.com. NS
Answer
The response has no answer records.
Authority
ti.com. 60 SOA oleibdm.itg.ti.com. hostmaster.ti.com. 2013108362 900 300 2419200 60
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0