<div dir="ltr"><div class="gmail_extra"><br><div class="gmail_quote">On Thu, Jun 1, 2017 at 8:28 AM, Peng Yonghua <span dir="ltr"><<a href="mailto:pyh@vodafonemail.de" target="_blank">pyh@vodafonemail.de</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Hi,<br>
<br>
Sorry I may be asking a low-end question.<br>
<br>
I dig this and find .uk is auth-resolved by a group of <a href="http://nic.uk" rel="noreferrer" target="_blank">nic.uk</a> name servers.<br>
<br>
$ dig <a href="http://org.uk" rel="noreferrer" target="_blank">org.uk</a>. ns @<a href="http://d.root-servers.net" rel="noreferrer" target="_blank">d.root-servers.net</a><br>
<br>
; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.62.rc1<wbr>.el6_9.2 <<>> <a href="http://org.uk" rel="noreferrer" target="_blank">org.uk</a>. ns @<a href="http://d.root-servers.net" rel="noreferrer" target="_blank">d.root-servers.net</a><br>
;; global options: +cmd<br>
;; Got answer:<br>
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 2021<br>
;; flags: qr rd; QUERY: 1, ANSWER: 0, AUTHORITY: 8, ADDITIONAL: 13<br>
;; WARNING: recursion requested but not available<br>
<br>
;; QUESTION SECTION:<br>
;<a href="http://org.uk" rel="noreferrer" target="_blank">org.uk</a>. IN NS<br>
<br>
;; AUTHORITY SECTION:<br>
uk. 172800 IN NS <a href="http://dns1.nic.uk" rel="noreferrer" target="_blank">dns1.nic.uk</a>.<br>
uk. 172800 IN NS <a href="http://dns4.nic.uk" rel="noreferrer" target="_blank">dns4.nic.uk</a>.<br>
uk. 172800 IN NS <a href="http://nsc.nic.uk" rel="noreferrer" target="_blank">nsc.nic.uk</a>.<br>
uk. 172800 IN NS <a href="http://nsd.nic.uk" rel="noreferrer" target="_blank">nsd.nic.uk</a>.<br>
uk. 172800 IN NS <a href="http://nsb.nic.uk" rel="noreferrer" target="_blank">nsb.nic.uk</a>.<br>
uk. 172800 IN NS <a href="http://dns3.nic.uk" rel="noreferrer" target="_blank">dns3.nic.uk</a>.<br>
uk. 172800 IN NS <a href="http://nsa.nic.uk" rel="noreferrer" target="_blank">nsa.nic.uk</a>.<br>
uk. 172800 IN NS <a href="http://dns2.nic.uk" rel="noreferrer" target="_blank">dns2.nic.uk</a>.<br>
<br>
;; ADDITIONAL SECTION:<br>
<a href="http://nsa.nic.uk" rel="noreferrer" target="_blank">nsa.nic.uk</a>. 172800 IN A 156.154.100.3<br>
<a href="http://nsb.nic.uk" rel="noreferrer" target="_blank">nsb.nic.uk</a>. 172800 IN A 156.154.101.3<br>
<a href="http://nsc.nic.uk" rel="noreferrer" target="_blank">nsc.nic.uk</a>. 172800 IN A 156.154.102.3<br>
<a href="http://nsd.nic.uk" rel="noreferrer" target="_blank">nsd.nic.uk</a>. 172800 IN A 156.154.103.3<br>
<a href="http://dns1.nic.uk" rel="noreferrer" target="_blank">dns1.nic.uk</a>. 172800 IN A <a href="tel:213.248.216.1" value="+12132482161" target="_blank">213.248.216.1</a><br>
<a href="http://dns2.nic.uk" rel="noreferrer" target="_blank">dns2.nic.uk</a>. 172800 IN A 103.49.80.1<br>
<a href="http://dns3.nic.uk" rel="noreferrer" target="_blank">dns3.nic.uk</a>. 172800 IN A <a href="tel:213.248.220.1" value="+12132482201" target="_blank">213.248.220.1</a><br>
<a href="http://dns4.nic.uk" rel="noreferrer" target="_blank">dns4.nic.uk</a>. 172800 IN A 43.230.48.1<br>
<a href="http://nsa.nic.uk" rel="noreferrer" target="_blank">nsa.nic.uk</a>. 172800 IN AAAA 2001:502:ad09::3<br>
<a href="http://dns1.nic.uk" rel="noreferrer" target="_blank">dns1.nic.uk</a>. 172800 IN AAAA 2a01:618:400::1<br>
<a href="http://dns2.nic.uk" rel="noreferrer" target="_blank">dns2.nic.uk</a>. 172800 IN AAAA 2401:fd80:400::1<br>
<a href="http://dns3.nic.uk" rel="noreferrer" target="_blank">dns3.nic.uk</a>. 172800 IN AAAA 2a01:618:404::1<br>
<a href="http://dns4.nic.uk" rel="noreferrer" target="_blank">dns4.nic.uk</a>. 172800 IN AAAA 2401:fd80:404::1<br>
<br>
;; Query time: 256 msec<br>
;; SERVER: 199.7.91.13#53(199.7.91.13)<br>
;; WHEN: Thu Jun 1 20:14:05 2017<br>
;; MSG SIZE rcvd: 444<br>
<br>
<br>
<br>
Then I dig this:<br>
<br>
$ dig <a href="http://org.uk" rel="noreferrer" target="_blank">org.uk</a>. ns @<a href="http://dns2.nic.uk" rel="noreferrer" target="_blank">dns2.nic.uk</a><br>
<br>
; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.62.rc1<wbr>.el6_9.2 <<>> <a href="http://org.uk" rel="noreferrer" target="_blank">org.uk</a>. ns @<a href="http://dns2.nic.uk" rel="noreferrer" target="_blank">dns2.nic.uk</a><br>
;; global options: +cmd<br>
;; Got answer:<br>
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 25645<br>
;; flags: qr aa rd; QUERY: 1, ANSWER: 8, AUTHORITY: 0, ADDITIONAL: 0<br>
;; WARNING: recursion requested but not available<br>
<br>
;; QUESTION SECTION:<br>
;<a href="http://org.uk" rel="noreferrer" target="_blank">org.uk</a>. IN NS<br>
<br>
;; ANSWER SECTION:<br>
<a href="http://org.uk" rel="noreferrer" target="_blank">org.uk</a>. 172800 IN NS <a href="http://nsc.nic.uk" rel="noreferrer" target="_blank">nsc.nic.uk</a>.<br>
<a href="http://org.uk" rel="noreferrer" target="_blank">org.uk</a>. 172800 IN NS <a href="http://dns3.nic.uk" rel="noreferrer" target="_blank">dns3.nic.uk</a>.<br>
<a href="http://org.uk" rel="noreferrer" target="_blank">org.uk</a>. 172800 IN NS <a href="http://dns1.nic.uk" rel="noreferrer" target="_blank">dns1.nic.uk</a>.<br>
<a href="http://org.uk" rel="noreferrer" target="_blank">org.uk</a>. 172800 IN NS <a href="http://dns4.nic.uk" rel="noreferrer" target="_blank">dns4.nic.uk</a>.<br>
<a href="http://org.uk" rel="noreferrer" target="_blank">org.uk</a>. 172800 IN NS <a href="http://nsd.nic.uk" rel="noreferrer" target="_blank">nsd.nic.uk</a>.<br>
<a href="http://org.uk" rel="noreferrer" target="_blank">org.uk</a>. 172800 IN NS <a href="http://dns2.nic.uk" rel="noreferrer" target="_blank">dns2.nic.uk</a>.<br>
<a href="http://org.uk" rel="noreferrer" target="_blank">org.uk</a>. 172800 IN NS <a href="http://nsa.nic.uk" rel="noreferrer" target="_blank">nsa.nic.uk</a>.<br>
<a href="http://org.uk" rel="noreferrer" target="_blank">org.uk</a>. 172800 IN NS <a href="http://nsb.nic.uk" rel="noreferrer" target="_blank">nsb.nic.uk</a>.<br>
<br>
;; Query time: 261 msec<br>
;; SERVER: 103.49.80.1#53(103.49.80.1)<br>
;; WHEN: Thu Jun 1 20:14:19 2017<br>
;; MSG SIZE rcvd: 176<br>
<br>
<br>
<br>
I think the data path should be: root nameservers -> .uk nameservers -> .<a href="http://org.uk" rel="noreferrer" target="_blank">org.uk</a> nameservers<br>
<br>
since .uk nameservers are the same with .<a href="http://org.uk" rel="noreferrer" target="_blank">org.uk</a> nameservers, so the reference from uk to <a href="http://org.uk" rel="noreferrer" target="_blank">org.uk</a> is not needed.<br>
<br>
Do I guess it right? thanks in advance.<br>
<br></blockquote><div><br></div><div>You are correct. The nameservers answer with the most specific referral that they have.</div><div><br></div><div>-- </div><div>Bob Harold</div><div><br></div><div> </div></div></div></div>