129.240.70.217.in-addr.arpa has no NS records.
NS records for this zone are defined at 240.70.217.in-addr.arpa.
NS records for this zone are defined at 240.70.217.in-addr.arpa.
Question and response
Question
dig 129.240.70.217.in-addr.arpa. NS
Answer
The response has no answer records.
Authority
240.70.217.in-addr.arpa. 86400 SOA dns1.dragonet.es. admin.dragonet.es. 2004092901 3600 600 3600000 86400
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0