Apex domains cannot have CNAME records.
Question and response
Question
dig tiscali.com. NS
Answer
tiscali.com. 5 NS murdock.tiscali.com.
tiscali.com. 5 NS hannibal.tiscali.com.
tiscali.com. 5 NS barakus.tiscali.com.
Authority
The response has no authority records.
Additional
barakus.tiscali.com. 5 A 213.205.32.90
murdock.tiscali.com. 5 A 213.205.36.90
hannibal.tiscali.com. 5 A 94.32.102.60
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0