ns4.he.net has no CNAME records.
Question and response
Question
dig ns4.he.net. NS
Answer
The response has no answer records.
Authority
he.net. 7359 SOA ns1.he.net. hostmaster.he.net. 202603030 10800 1800 604800 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0