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<p class="MsoNormal"><span style="color:#1F497D">Yes sure.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">For that you need the Authoritative un public IP with the “allow-recursion” disabled, and the recursor configured as I told you, with the “allow-from=127.0.0.0/8,192.168.0.0/16,172.16.0.0/16 … you know … your
internal netmasks”<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">Another thing you can do to improve the performance on the recursor is to enable the forward-zones directly to your auth server.
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">Like … forward-zones=mydomain1.com=AuthServerIP1;AuthServerIP2,mydomain2.com= AuthServerIP1;AuthServerIP2<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">Just to avoid have to wait until any change on your domain were replicated to the root servers.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">Which external CNAME?<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">Ale<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span lang="EN-US" style="mso-fareast-language:EN-GB">From:</span></b><span lang="EN-US" style="mso-fareast-language:EN-GB"> Michael Hasenburger [mailto:Michael.Hasenburger@marel.at]
<br>
<b>Sent:</b> miércoles, 14 de septiembre de 2016 12:08<br>
<b>To:</b> Alejandro Adroher Mellado <alejandro.adroher@omniaccess.com>; pdns-users@mailman.powerdns.com<br>
<b>Subject:</b> AW: Need a solution to use an resolver for external CNAME's<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span lang="DE-AT" style="color:#1F497D">> </span><span style="color:#1F497D">I have note very clear what you are looking for …. It seems you need an Authoritative for your domains (which can be queried by everyone) and also a recursor
for internal use only.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="DE-AT" style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="DE-AT" style="color:#1F497D">Yes, that’s exactly what we want.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="DE-AT" style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="DE-AT" style="color:#1F497D">Actually our DNS server is fully opened and we got an information from cert-bund.de that we‘re frail for a DNS Amplification attack. My idea is to close the recursor for public. But it doesn’t query
external CNAME for example.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="DE-AT" style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="DE-AT" style="color:#1F497D">Is it possible to configure?<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="DE-AT" style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="DE-AT" style="color:#1F497D">Thank you very much.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="DE-AT" style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="DE-AT" style="color:#1F497D">BR Mike<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="DE-AT" style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="DE-AT" style="color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span lang="DE" style="font-size:10.0pt;font-family:"Tahoma",sans-serif;mso-fareast-language:DE-AT">Von:</span></b><span lang="DE" style="font-size:10.0pt;font-family:"Tahoma",sans-serif;mso-fareast-language:DE-AT"> Alejandro Adroher
Mellado [<a href="mailto:alejandro.adroher@omniaccess.com">mailto:alejandro.adroher@omniaccess.com</a>]
<br>
<b>Gesendet:</b> Mittwoch, 14. September 2016 11:48<br>
<b>An:</b> Michael Hasenburger; <a href="mailto:pdns-users@mailman.powerdns.com">
pdns-users@mailman.powerdns.com</a><br>
<b>Betreff:</b> RE: Need a solution to use an resolver for external CNAME's<o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="DE-AT"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">Hi, <o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">A resolver by definition goes to the root servers to find answers to the queries received.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">If you want to ask for an external CNAME, you need a recursor, but using f.e. the “allow-from=172.16.0.0/16” (being this your internal network), close your recursor service to the external world. You could use
it, but I’m not.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">You say:<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">“</span><span lang="DE-AT" style="color:#1F497D">We want a public DNS server, but resolve queries for existing database entries only. Seems not possible to configure.</span><span style="color:#1F497D">”<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">For that having only an Authoritative Service is enough.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">I have note very clear what you are looking for …. It seems you need an Authoritative for your domains (which can be queried by everyone) and also a recursor for internal use only.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">Can you clarify this for me? <o:p>
</o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">XD<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">Ale<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span lang="EN-US" style="mso-fareast-language:EN-GB">From:</span></b><span lang="EN-US" style="mso-fareast-language:EN-GB"> Michael Hasenburger [<a href="mailto:Michael.Hasenburger@marel.at">mailto:Michael.Hasenburger@marel.at</a>]
<br>
<b>Sent:</b> miércoles, 14 de septiembre de 2016 11:34<br>
<b>To:</b> Alejandro Adroher Mellado <<a href="mailto:alejandro.adroher@omniaccess.com">alejandro.adroher@omniaccess.com</a>>;
<a href="mailto:pdns-users@mailman.powerdns.com">pdns-users@mailman.powerdns.com</a><br>
<b>Subject:</b> AW: Need a solution to use an resolver for external CNAME's<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span lang="DE-AT" style="color:#1F497D">Hi Ale,</span><span lang="DE-AT"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="DE-AT" style="color:#1F497D"> </span><span lang="DE-AT"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="DE-AT" style="color:#1F497D">I also configured pdns-resolver with allow-from localhost, but it does resolve all request from powerdns.</span><span lang="DE-AT"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="DE-AT" style="color:#1F497D">We want a public DNS server, but resolve queries for existing database entries only. Seems not possible to configure.</span><span lang="DE-AT"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="DE-AT" style="color:#1F497D"> </span><span lang="DE-AT"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="DE-AT" style="color:#1F497D">BR Mike</span><span lang="DE-AT"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="DE-AT" style="color:#1F497D"> </span><span lang="DE-AT"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="DE-AT" style="color:#1F497D"> </span><span lang="DE-AT"><o:p></o:p></span></p>
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<p class="MsoNormal"><b><span lang="DE" style="font-size:10.0pt;font-family:"Tahoma",sans-serif;mso-fareast-language:DE-AT">Von:</span></b><span lang="DE" style="font-size:10.0pt;font-family:"Tahoma",sans-serif;mso-fareast-language:DE-AT"> Alejandro Adroher
Mellado [<a href="mailto:alejandro.adroher@omniaccess.com">mailto:alejandro.adroher@omniaccess.com</a>]
<br>
<b>Gesendet:</b> Mittwoch, 14. September 2016 10:48<br>
<b>An:</b> EDV-Techniker; <a href="mailto:pdns-users@mailman.powerdns.com">pdns-users@mailman.powerdns.com</a><br>
<b>Betreff:</b> RE: Need a solution to use an resolver for external CNAME's</span><span lang="DE-AT"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="DE-AT"> <o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">Hi Mike, </span><span lang="DE-AT"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"> </span><span lang="DE-AT"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">Use ACL to close your resolver</span><span lang="DE-AT"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"> </span><span lang="DE-AT"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">allow-from=your internal allowed netmasks</span><span lang="DE-AT"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"> </span><span lang="DE-AT"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">Ale</span><span lang="DE-AT"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"> </span><span lang="DE-AT"><o:p></o:p></span></p>
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<p class="MsoNormal"><b><span lang="EN-US" style="mso-fareast-language:EN-GB">From:</span></b><span lang="EN-US" style="mso-fareast-language:EN-GB"> Pdns-users [<a href="mailto:pdns-users-bounces@mailman.powerdns.com">mailto:pdns-users-bounces@mailman.powerdns.com</a>]
<b>On Behalf Of </b>EDV-Techniker<br>
<b>Sent:</b> miércoles, 14 de septiembre de 2016 10:08<br>
<b>To:</b> <a href="mailto:pdns-users@mailman.powerdns.com">pdns-users@mailman.powerdns.com</a><br>
<b>Subject:</b> [Pdns-users] Need a solution to use an resolver for external CNAME's</span><span lang="DE-AT"><o:p></o:p></span></p>
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<p class="MsoNormal"> <span lang="DE-AT"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="DE-AT">Hi,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="DE-AT"> <o:p></o:p></span></p>
<p class="MsoNormal"><span lang="DE-AT">we want using a nameserver for our domains only. I can be done without configure a resolver. Works fine but if query f.e. an external CNAME, which A record doesn’t exist at our database, then PowerDNS doesn’t resolve.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="DE-AT"> <o:p></o:p></span></p>
<p class="MsoNormal"><span lang="DE-AT">Using a resolver does solve this problem. But now the DNS server is open and frail for attacks.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="DE-AT"> <o:p></o:p></span></p>
<p class="MsoNormal"><span lang="DE-AT">Is there a solution to use an resolver to query existing database entries only?<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="DE" style="mso-fareast-language:DE-AT"> </span><span lang="DE-AT"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="DE" style="mso-fareast-language:DE-AT">BR Mike</span><span lang="DE-AT"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="DE" style="mso-fareast-language:DE-AT">MAREL IT solutions</span><span lang="DE-AT"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="DE-AT"> <o:p></o:p></span></p>
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