Apex domains cannot have CNAME records.
Question and response
Question
dig dcnet.tr. NS
Answer
dcnet.tr. 5 NS akyuz.dcnet.tr.
dcnet.tr. 5 NS ns1.dcnet.tr.
dcnet.tr. 5 NS eregli.dcnet.tr.
Authority
The response has no authority records.
Additional
ns1.dcnet.tr. 5 A 188.132.235.3
akyuz.dcnet.tr. 5 A 188.132.235.5
eregli.dcnet.tr. 5 A 188.132.235.5
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0