webmail.dilmail.com has no CNAME records.
Question and response
Question
dig webmail.dilmail.com. NS
Answer
The response has no answer records.
Authority
dilmail.com. 3484 SOA ns1.dildns.com. dinesh.dil.in. 2012100905 3600 3600 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0