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<div class="moz-cite-prefix">On 11/13/2018 11:04 AM, Frank Liu
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:CAOXPdC_R_oxUZ0AKD=jdpfyjUTobnj8i56RmbNLEvmDemoQCxQ@mail.gmail.com">
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<div>Hi,</div>
<div><br>
</div>
<div>Is there a RFC determining which nameserver to use if there
is a conflicting subdomain delegation?</div>
<div><br>
</div>
<div>eg:</div>
<div>In the zone of <a href="http://a.com"
moz-do-not-send="true">a.com</a>, there are two NS
delegations:</div>
<div><br>
</div>
<div><a href="http://b.a.com" moz-do-not-send="true">b.a.com</a>
NS host1</div>
<div><a href="http://c.b.a.com" moz-do-not-send="true">c.b.a.com</a>
NS host2</div>
<div><br>
</div>
<div>On host1 in zone <a href="http://b.a.com"
moz-do-not-send="true">b.a.com</a>, there is</div>
<div><a href="http://c.b.a.com" moz-do-not-send="true">c.b.a.com</a>
NS host3</div>
<div><br>
</div>
<div>As you can see, there is a conflicting delegation for <a
href="http://c.b.a.com" moz-do-not-send="true">c.b.a.com</a>.
If I look a name <a href="http://d.c.b.a.com"
moz-do-not-send="true">d.c.b.a.com</a>, will the nameserver
host2 or host3 be used?</div>
<div>dig +trace seems to go to host2, but bind9 as a resolver
goes to host3.</div>
<div>(the test was done on a centos7).</div>
<div><br>
</div>
<div>Any ideas?</div>
<div>Thanks!<br>
</div>
</div>
<br>
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</blockquote>
<p>I would expect that behavior if the Bind9 resolver was setup to
query host1. If bind9 queries a server that is authoritive for
b.a.com, I would expect that result. If the bind9 resolver is
setup to query a recursive only server(other than host1), I would
expect the same behavior as the +trace result.</p>
<p>so I think the answer is dependant on how your bind9 resolver is
configured.<br>
</p>
<p>Lyle Giese<br>
</p>
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