Non-authoritative answer simply means the answer is not fetched from the authoritative DNS server for the queried domain name.įirst you have to understand how DNS system works. All other nameservers, non-authoritative nameservers, get their NS records from the authoritative servers somewhere down the line. Those servers are the authority, (or source) for what are valid names in Google's domains, and what aren't. If I changed my configured DNS server to one of the ones in that list, and then did an nslookup against, I'd get an authoritative answer back. The list of authoritative nameservers for Google is below (from ).
They aren't Google's nameservers, so they're not the authoritative source that creates the NS records. (Either from my ISP, or my domain.) It would come back as non-authoritative because neither my ISP's nameservers, nor my own are in the list of nameservers for. So, for example, If I did an nslookup of right now, I would get a response from one of my configured nameservers.
Nameservers that aren't authoritative are getting their answers second (or third or fourth.) hand - just relaying the information along from somewhere else. It's basically a distinction between a nameserver that's an official nameserver for the domain you're querying, and a nameserver that isn't. An authoritative answer comes from a nameserver that is considered authoritative for the domain which it's returning a record for (one of the nameservers in the list for the domain you did a lookup on), and a non-authoritative answer comes from anywhere else (a nameserver not in the list for the domain you did a lookup on). Basically, it's what the name says it is.
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