mail8.viatel.com has no NS records.
NS records for this zone are defined at viatel.com.
NS records for this zone are defined at viatel.com.
Question and response
Question
dig mail8.viatel.com. NS
Answer
The response has no answer records.
Authority
viatel.com. 86400 SOA dns1-auth.viatel.net. hostmaster.viatel.net. 2023092500 28800 7200 604800 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0