mail.vhsmail.vodafone.com has no NS records.
NS records for this zone are defined at vodafone.com.
NS records for this zone are defined at vodafone.com.
Question and response
Question
dig mail.vhsmail.vodafone.com. NS
Answer
The response has no answer records.
Authority
vodafone.com. 900 SOA ns1.vodafone.com. hostmaster.vodafone.com. 2008110001 28800 7200 604800 900
Additional
. 0 OPT ; payload 1220, xrcode 0, version 0, flags 0