Apex domains cannot have CNAME records.
Question and response
Question
dig sdns.satyam.net.in. NS
Answer
sdns.satyam.net.in. 5 NS a.ns.sdns.satyam.net.in.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0