rt2perf.opsx.nl has no CNAME records.
Question and response
Question
dig rt2perf.opsx.nl. NS
Answer
The response has no answer records.
Authority
opsx.nl. 120 SOA ns03.etherned.nl. networking.ipvisie.com. 2025121601 21600 3600 604800 120
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0