98.232.79.188.dynamic.jazztel.es has no CNAME records.
Question and response
Question
dig 98.232.79.188.dynamic.jazztel.es. NS
Answer
The response has no answer records.
Authority
232.79.188.dynamic.jazztel.es. 10621 SOA dns1.jazzvisp.com. admin.jazztel.es. 2011021400 7200 7200 2419200 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0