exchange.plpod.ru has no NS records.
NS records for this zone are defined at plpod.ru.
NS records for this zone are defined at plpod.ru.
Question and response
Question
dig exchange.plpod.ru. NS
Answer
The response has no answer records.
Authority
plpod.ru. 300 SOA ns.pledpodushkin.ru. admin.pledpodushkin.ru. 412202515 10800 3600 604800 604800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0