<div dir="ltr">Hello PowerDNS Users,<div><br></div><div>I know this has been discussed many times but I'd like to ask for some hints how to deal with situation I met. It's about how PowerDNS is responding with CNAME records pointing to 'external' name. Case example:</div>
<div><br></div><div><div>; <<>> DiG 9.7.3 <<>> <a href="http://cdn.mydomain.net">cdn.mydomain.net</a> @<a href="http://dns.mydomain.net">dns.mydomain.net</a></div><div>;; global options: +cmd</div>
<div>;; Got answer:</div><div>;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 19922</div><div>;; flags: qr aa rd; QUERY: 1, ANSWER: 1, AUTHORITY: 1, ADDITIONAL: 0</div><div>;; WARNING: recursion requested but not available</div>
<div><br></div><div>;; QUESTION SECTION:</div><div>;<a href="http://cdn.mydomain.net">cdn.mydomain.net</a>. IN A</div><div><br></div><div>;; ANSWER SECTION:</div><div><a href="http://cdn.mydomain.net">cdn.mydomain.net</a>. 3600 IN CNAME <a href="http://randomstr.cloudfront.net">randomstr.cloudfront.net</a>.</div>
<div><br></div><div>;; AUTHORITY SECTION:</div><div>. 3600 IN SOA <a href="http://dns.mydomain.net">dns.mydomain.net</a>. <a href="http://noc.mydomain.net">noc.mydomain.net</a>. 2012042301 10800 3600 604800 300</div>
<div><br></div><div>;; Query time: 205 msec</div><div>;; SERVER: 1xx.1xx.1xx.1xx#53(1xx.1xx.1xx.1xx)</div><div>;; WHEN: Fri May 24 20:54:31 2013</div><div>;; MSG SIZE rcvd: 143</div><div><br></div><div style>My concern is NXDOMAIN status. As per discussions and RFC's the answer is correct. I understand that but the problem is there are some dns resolver which just don't get it ;).</div>
<div style>Clients of mine started report they can't get cdn network to work with their sites. After investigation everything comes to common point - the ISP. All of them are using UPC broadband in Europe. When they query default UPC's name servers they are getting 'couldn't find host' errors. It looks like this:</div>
<div style><span style="background-color:rgb(247,250,253);color:rgb(0,0,0);font-family:'Lucida Grande','Lucida Sans Unicode',Verdana,Arial,sans-serif;font-size:12px"><br></span></div><div style><span style="background-color:rgb(247,250,253);color:rgb(0,0,0);font-family:'Lucida Grande','Lucida Sans Unicode',Verdana,Arial,sans-serif;font-size:12px">nslookup cdn.</span><a href="http://mydomain.net">mydomain.net</a><br>
</div><div style><span style="color:rgb(0,0,0);font-family:'Lucida Grande','Lucida Sans Unicode',Verdana,Arial,sans-serif;font-size:12px;background-color:rgb(247,250,253)">Server: <a href="http://ns01.upclive.nl">ns01.upclive.nl</a></span><br style="list-style:none;color:rgb(0,0,0);font-family:'Lucida Grande','Lucida Sans Unicode',Verdana,Arial,sans-serif;font-size:12px;background-color:rgb(247,250,253)">
<span style="color:rgb(0,0,0);font-family:'Lucida Grande','Lucida Sans Unicode',Verdana,Arial,sans-serif;font-size:12px;background-color:rgb(247,250,253)">Address: 62.179.104.196</span><br style="list-style:none;color:rgb(0,0,0);font-family:'Lucida Grande','Lucida Sans Unicode',Verdana,Arial,sans-serif;font-size:12px;background-color:rgb(247,250,253)">
<span style="color:rgb(0,0,0);font-family:'Lucida Grande','Lucida Sans Unicode',Verdana,Arial,sans-serif;font-size:12px;background-color:rgb(247,250,253)">*** <a href="http://ns01.upclive.nl">ns01.upclive.nl</a> could not find cdn.</span><a href="http://mydomain.net">mydomain.net</a><span style="background-color:rgb(247,250,253);color:rgb(0,0,0);font-family:'Lucida Grande','Lucida Sans Unicode',Verdana,Arial,sans-serif;font-size:12px">: Non-existent domain</span></div>
<div style><br style="list-style:none;color:rgb(0,0,0);font-family:'Lucida Grande','Lucida Sans Unicode',Verdana,Arial,sans-serif;font-size:12px;background-color:rgb(247,250,253)"><span style="color:rgb(0,0,0);font-family:'Lucida Grande','Lucida Sans Unicode',Verdana,Arial,sans-serif;font-size:12px;background-color:rgb(247,250,253)">tracert cdn.</span><a href="http://mydomain.net">mydomain.net</a><br style="list-style:none;color:rgb(0,0,0);font-family:'Lucida Grande','Lucida Sans Unicode',Verdana,Arial,sans-serif;font-size:12px;background-color:rgb(247,250,253)">
<span style="color:rgb(0,0,0);font-family:'Lucida Grande','Lucida Sans Unicode',Verdana,Arial,sans-serif;font-size:12px;background-color:rgb(247,250,253)">Could not convert the target name of cdn.</span><a href="http://mydomain.net">mydomain.net</a><span style="background-color:rgb(247,250,253);color:rgb(0,0,0);font-family:'Lucida Grande','Lucida Sans Unicode',Verdana,Arial,sans-serif;font-size:12px">.</span></div>
<div style><span style="background-color:rgb(247,250,253);color:rgb(0,0,0);font-family:'Lucida Grande','Lucida Sans Unicode',Verdana,Arial,sans-serif;font-size:12px"><br></span></div><div style><font color="#000000" face="Lucida Grande, Lucida Sans Unicode, Verdana, Arial, sans-serif"><span style="font-size:12px">Seems UPC's dns resolvers rely on dns response status and discard CNAME answer. Now the question comes in: who is wrong?</span></font></div>
<div style><font color="#000000" face="Lucida Grande, Lucida Sans Unicode, Verdana, Arial, sans-serif"><span style="font-size:12px">There is hundreds of thousands clients in Europe using UPC services. I have the same reports from people living in Netherlands, Czech Rep. and Poland. it's impossible for me to tell all of them to change dns resolvers to other servers. I would rather bend the rules and adjust PowerDNS status to return NOERROR for answers like this and have all these people off my back.</span></font></div>
<div style><font color="#000000" face="Lucida Grande, Lucida Sans Unicode, Verdana, Arial, sans-serif"><span style="font-size:12px">Maybe someone from UPC is looking on this list and can share thoughts. Anyway, any advice on how to deal with this situation would be much appreciated.</span></font></div>
<div style><font color="#000000" face="Lucida Grande, Lucida Sans Unicode, Verdana, Arial, sans-serif"><span style="font-size:12px"><br></span></font></div><div style><font color="#000000" face="Lucida Grande, Lucida Sans Unicode, Verdana, Arial, sans-serif"><span style="font-size:12px">Regards,</span></font></div>
<div style><font color="#000000" face="Lucida Grande, Lucida Sans Unicode, Verdana, Arial, sans-serif"><span style="font-size:12px">Pawel Panek</span></font></div>
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