unknown.yahoo.com has no NS records.
NS records for this zone are defined at yahoo.com.
NS records for this zone are defined at yahoo.com.
Question and response
Question
dig unknown.yahoo.com. NS
Answer
The response has no answer records.
Authority
yahoo.com. 600 SOA ns1.yahoo.com. hostmaster.yahoo-inc.com. 2026022102 3600 300 1814400 600
Additional
. 0 OPT ; payload 1272, xrcode 0, version 0, flags 0