mta1b1.update.trulia.com has no NS records.
NS records for this zone are defined at trulia.com.
NS records for this zone are defined at trulia.com.
Question and response
Question
dig mta1b1.update.trulia.com. NS
Answer
The response has no answer records.
Authority
trulia.com. 900 SOA ns-1430.awsdns-50.org. hostmaster.trulia.com. 1 7200 900 1209600 30
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0