<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
</head>
<body>
<p>Hi,</p>
<div class="moz-cite-prefix">On 11/21/25 11:41, Emmanuel Fusté
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:dfbccf2d-77c7-488d-bb10-f27164499551@gmail.com">Hi Joe,
<br>
<br>
Le 20/11/2025 à 19:07, Joe Abley a écrit :
<br>
<blockquote type="cite">Hi Emmanuel,
<br>
<br>
On 20 Nov 2025, at 16:53, Emmanuel Fusté
<a class="moz-txt-link-rfc2396E" href="mailto:manu.fuste@gmail.com"><manu.fuste@gmail.com></a> wrote:
<br>
<br>
<blockquote type="cite">With a colleague we found by accident
read world records served by Cloudflare DNS which are breaking
the DNS data model: multiple possible CNAME values for a same
record leading to possible resolver's cache pollution.
<br>
As the way to get one value or another is trivial, the way to
control the resolver cached value is trivial too.
<br>
We did not find how Cloudflare DNS features and zone content
where used/combined to generate this behavior which is surely
unexpected for the zone operator.
<br>
Is there some Cloudflare people here to whom I could provide
the zone/records details to see if it is an expected/assumed
behavior or a subtle corner case bug ?
<br>
</blockquote>
There are a few of us here. Feel free to ping me off-list!
<br>
<br>
<br>
Joe
<br>
</blockquote>
Thank you ! Details transmited off-list. <br>
</blockquote>
<p><span class="HwtZe" lang="en"><span class="jCAhz ChMk0b"><span
class="ryNqvb">Please keep us informed if this case could
cause problems for other resolver operators as well or is
otherwise relevant to them.</span></span></span></p>
<p><span class="HwtZe" lang="en"><span class="jCAhz ChMk0b"><span
class="ryNqvb">Winfried</span></span></span></p>
</body>
</html>