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