mx1.cetelem.pt has no NS records.
NS records for this zone are defined at cetelem.pt.
NS records for this zone are defined at cetelem.pt.
Question and response
Question
dig mx1.cetelem.pt. NS
Answer
The response has no answer records.
Authority
cetelem.pt. 600 SOA ns1.bnpparibas.com. i_names.bnpparibas.com. 120 14400 3600 2419200 600
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0