<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">Hi Roberto,<br class=""><div class="">
<div style="color: rgb(0, 0, 0); letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div style="color: rgb(0, 0, 0); letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div style="color: rgb(0, 0, 0); letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div style="color: rgb(0, 0, 0); letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><br class=""></div></div></div></div></div><div><blockquote type="cite" class=""><div class="">On 17 May 2018, at 16:25, Roberto Carna <<a href="mailto:robertocarna36@gmail.com" class="">robertocarna36@gmail.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div class="">Dear Tony, so you say that it's impossible what I want...<br class=""><br class="">In this scenario that my two DNS servers respond queries at the same<br class="">time, suppose the primary server goes down....how do clients know that<br class="">they have to query the secondary DNS server at this moment?<br class=""><br class=""></div></div></blockquote><blockquote type="cite" class=""><div class=""><div class="">Thanks again.<br class=""></div></div></blockquote><div><br class=""></div><div>since your servers are Authoritative, clients won’t query them directly, but it’s rather Recursive DNS servers who will do so.</div><div>If one of your DNS server is unreachable, Recursive servers will try the next one(s).</div><div><br class=""></div><div>Cheers,</div><div>Nico</div><div><br class=""></div><br class=""><blockquote type="cite" class=""><div class=""><div class=""><br class="">2018-05-17 11:19 GMT-03:00 Tony Finch <<a href="mailto:dot@dotat.at" class="">dot@dotat.at</a>>:<br class=""><blockquote type="cite" class="">Roberto Carna <<a href="mailto:robertocarna36@gmail.com" class="">robertocarna36@gmail.com</a>> wrote:<br class=""><blockquote type="cite" class=""><br class="">I always believed that all the client queries coming from Internet go<br class="">to the DNS primary server, and if it is down, just in this case go to<br class="">the DNS secondary server.<br class=""></blockquote><br class="">It can't happen that way because there's no way for a resolver to tell<br class="">which is which.<br class=""><br class="">Tony.<br class="">--<br class="">f.anthony.n.finch <<a href="mailto:dot@dotat.at" class="">dot@dotat.at</a>> <a href="http://dotat.at/" class="">http://dotat.at/</a><br class="">Hebrides: Southeast 4, veering south 5 or 6, then veering west later. Moderate<br class="">or rough. Rain later. Good, occasionally moderate.<br class=""></blockquote>_______________________________________________<br class="">Please visit <a href="https://lists.isc.org/mailman/listinfo/bind-users" class="">https://lists.isc.org/mailman/listinfo/bind-users</a> to unsubscribe from this list<br class=""><br class="">bind-users mailing list<br class=""><a href="mailto:bind-users@lists.isc.org" class="">bind-users@lists.isc.org</a><br class="">https://lists.isc.org/mailman/listinfo/bind-users<br class=""></div></div></blockquote></div><br class=""></body></html>