In attempt to help better understanding of how name servers for a domain are distributed, today I've introducted an experimental test on DNSInspect. This test will display distribution of name servers among Autonomous Systems.
Name servers should be dispersed (topologically and geographically) across the Internet to avoid risk of single point of failure (RFC 2182).
What is ASN?
ASN (Autonomous System Number) is a 32 bit number used in BGP routing which uniquely identifies each network on the Internet.
This test resolves names for each name server, fetches ASN for each IPv4 address and warns users if all IP addresses are located in a single ASN.