Find IP PTR record name servers

host 8.8.8.8
8.8.8.8.in-addr.arpa domain name pointer google-public-dns-a.google.com

host -t ns 8.8.8.in-addr.arpa
8.8.8.in-addr.arpa name server ns2.google.com.
8.8.8.in-addr.arpa name server ns3.google.com.
8.8.8.in-addr.arpa name server ns1.google.com.
8.8.8.in-addr.arpa name server ns4.google.com.