ns2.world-serv.com has no NS records.
NS records for this zone are defined at world-serv.com.
NS records for this zone are defined at world-serv.com.
Question and response
Question
dig ns2.world-serv.com. NS
Answer
The response has no answer records.
Authority
world-serv.com. 300 SOA ns.rackspace.com. hostmaster.rackspace.com. 1726684710 86400 7200 604800 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0