On: D. J. Bernstein

[shawnps]

Is there a way to find out for any given domain how many actual servers hand out responses to other DNS servers to hold in their caches?

[wmf → shawnps]

You can use WHOIS or dig, e.g.

$ dig yp.to ns

; <<>> DiG 9.4.3-P3 <<>> yp.to ns ;; global options: printcmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 63068 ;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION: ;yp.to. IN NS

;; ANSWER SECTION: yp.to. 184700 IN NS b.ns.yp.to. yp.to. 184700 IN NS f.ns.yp.to.

[nailer → shawnps]

dnstracer can show you that and much more. A great tool, shame nobody's heard of it.