ns4.savvis.net has no CNAME records.
Question and response
Question
dig ns4.savvis.net. NS
Answer
The response has no answer records.
Authority
savvis.net. 272 SOA ns2.savvis.net. abuse.aup.lumen.com. 2260109000 3600 1800 604800 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0