dns2.castle-it.net has no NS records.
NS records for this zone are defined at castle-it.net.
NS records for this zone are defined at castle-it.net.
Question and response
Question
dig dns2.castle-it.net. NS
Answer
The response has no answer records.
Authority
castle-it.net. 180 SOA castle-it.net. ythomas.castle-it.fr. 2020120401 3600 3600 1209600 604800
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0