blue.foundationdns.net has no NS records.
NS records for this zone are defined at foundationdns.net.
NS records for this zone are defined at foundationdns.net.
Question and response
Question
dig blue.foundationdns.net. NS
Answer
The response has no answer records.
Authority
foundationdns.net. 1800 SOA blue.foundationdns.com. dns.cloudflare.com. 2397474191 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0