filtering.netsolir.com has no CNAME records.
Question and response
Question
dig filtering.netsolir.com. NS
Answer
The response has no answer records.
Authority
netsolir.com. 3600 SOA ns1.netsolir.com. postmaster.netsolir.com. 2022011229 14400 3600 604800 14400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0