mail57.atl11.rsgsv.net has no NS records.
NS records for this zone are defined at rsgsv.net.
NS records for this zone are defined at rsgsv.net.
Question and response
Question
dig mail57.atl11.rsgsv.net. NS
Answer
The response has no answer records.
Authority
rsgsv.net. 86400 SOA pdns177.ultradns.com. dev.mailchimp.com. 2012051534 10800 3600 2592000 86400
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0