mail3.fortis.lu has no NS records.
NS records for this zone are defined at fortis.lu.
NS records for this zone are defined at fortis.lu.
Question and response
Question
dig mail3.fortis.lu. NS
Answer
The response has no answer records.
Authority
fortis.lu. 10800 SOA ns1.gandi.net. hostmaster.gandi.net. 1773273600 10800 3600 604800 10800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0