smtp41.clm.net4all.ch has no NS records.
NS records for this zone are defined at clm.net4all.ch.
NS records for this zone are defined at clm.net4all.ch.
Question and response
Question
dig smtp41.clm.net4all.ch. NS
Answer
The response has no answer records.
Authority
clm.net4all.ch. 3600 SOA dns01.net4all-dns.com.clm.net4all.ch. hostmaster.net4all-dns.com. 2018101803 10800 3600 2592000 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0