mx4.hin.ch has no NS records.
NS records for this zone are defined at hin.ch.
NS records for this zone are defined at hin.ch.
Question and response
Question
dig mx4.hin.ch. NS
Answer
The response has no answer records.
Authority
hin.ch. 900 SOA ns-1774.awsdns-29.co.uk. awsdns-hostmaster.amazon.com. 1 7200 900 1209600 86400
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0