z1a.envoke.com has no NS records.
NS records for this zone are defined at envoke.com.
NS records for this zone are defined at envoke.com.
Question and response
Question
dig z1a.envoke.com. NS
Answer
The response has no answer records.
Authority
envoke.com. 180 SOA ns10.digicertdns.com. dns.digicertdns.com. 2009010263 43200 3600 1209600 180
Additional
. 0 OPT ; payload 1280, xrcode 0, version 0, flags 0