Google DNS --- Figuring out which DNS Cluster you are using

Thu Aug 24 00:53:58 UTC 2017

If Google was being sensible the servers would just return the
information along with the answer.  They all support EDNS.

	e.g. dig +nsid @8.8.8.8

This is the type of thing the NSID (RFC 5001) was designed to do.
It just requires Google to configure the servers to return a id.
You would then back something like this.  In this case the nsid is
the hostname but it can be anything you like it to be.  A value
that makes sense to most people or a value that only make sense
to a Google.

; <<>> DiG 9.12.0-pre-alpha+hotspot+add-prefetch+marka <<>> +nsid .
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 38770
;; flags: qr rd ra ad; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
; NSID: 72 6f 63 6b 2e 64 76 2e 69 73 63 2e 6f 72 67 ("rock.dv.isc.org")
; COOKIE: f58c358da14bc19476e2331f599e21c452df41a06367d78d (good)
;; QUESTION SECTION:
;.				IN	A

;; AUTHORITY SECTION:
.			10773	IN	SOA	a.root-servers.net. nstld.verisign-grs.com. 2017082301 1800 900 604800 86400

;; Query time: 0 msec
;; SERVER: 127.0.0.1#53(127.0.0.1)
;; WHEN: Thu Aug 24 10:45:56 AEST 2017
;; MSG SIZE  rcvd: 150

-- 
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: marka at isc.org