210.208-223.245.2.189.in-addr.arpa has no NS records.
NS records for this zone are defined at 208-223.245.2.189.in-addr.arpa.
NS records for this zone are defined at 208-223.245.2.189.in-addr.arpa.
Question and response
Question
dig 210.208-223.245.2.189.in-addr.arpa. NS
Answer
The response has no answer records.
Authority
208-223.245.2.189.in-addr.arpa. 86400 SOA ns.embratel.net.br. admin.embratel.net.br. 2018080801 3600 900 604800 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0