1.125.2.81.in-addr.arpa has no NS records.
NS records for this zone are defined at 125.2.81.in-addr.arpa.
NS records for this zone are defined at 125.2.81.in-addr.arpa.
Question and response
Question
dig 1.125.2.81.in-addr.arpa. NS
Answer
The response has no answer records.
Authority
125.2.81.in-addr.arpa. 3600 SOA auth.primary-dns.co.uk. support.aa.net.uk. 1774210715 10800 3600 1209600 600
Additional
. 0 OPT ; payload 65000, xrcode 0, version 0, flags 0