Apex domains cannot have CNAME records.
Question and response
Question
dig hbone.hu. NS
Answer
hbone.hu. 4 NS kubiac.iif.hu.
hbone.hu. 4 NS ns2.sztaki.hbone.hu.
hbone.hu. 4 NS ns2.iif.hu.
Authority
The response has no authority records.
Additional
ns2.iif.hu. 4 A 193.225.12.59
ns2.sztaki.hbone.hu. 4 A 193.225.13.116
kubiac.iif.hu. 4 A 212.108.209.114
ns2.sztaki.hbone.hu. 4 AAAA 2001:738:0:302:0:0:0:116
kubiac.iif.hu. 4 AAAA 2001:1aa1:14:0:0:0:0:114
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0