Anomaly
http://use-application-dns.net/
DNS tampering
Jersey
Country
AS8681
Network
March 22, 2020, 1:30 AM UTC
Date & Time
Websites
Websites
Web Connectivity Test
Runtime: 4s

On Mar 22, 2020 1:30 AM, http://use-application-dns.net/ presented signs of DNS tampering on AS8681 in Jersey. This might mean that http://use-application-dns.net/ was blocked, but false positives can occur. Please explore the network measurement data below.

Failures

HTTP Experiment
null
DNS Experiment
null
Control
null

DNS Queries

Resolver:
74.125.47.132
Query:
IN A use-application-dns.net
Engine:
system
Name
Class
TTL
Type
DATA
@
IN
CNAME
use-application-dns.net
@
IN
A
63.245.208.212

TCP Connections

Connection to 63.245.208.212:80 succeeded.

HTTP Requests

URL
GET https://support.mozilla.org/en-US/kb/canary-domain-use-application-dnsnet
Response Headers
Content-Length:
40589
strict-transport-security:
max-age=31536000
X-Robots-Tag:
noodp
x-content-type-options:
nosniff
Set-Cookie:
csrftoken=5gIIIV9GoVeJiLpGqPLHyekpD4DdROnCviLp5rGXRWKTmmkLsbTFB9nS0Ya5JU3U; expires=Sun, 21-Mar-2021 01:30:42 GMT; Max-Age=31449600; Path=/
Expires:
Sun, 22 Mar 2020 01:30:42 GMT
Vary:
X-Mobile, User-Agent, Cookie
Server:
meinheld/0.6.1
Connection:
keep-alive
x-xss-protection:
1; mode=block
Cache-Control:
no-cache, no-store, must-revalidate, max-age=0
X-Backend-Server:
sumo-prod-web-5d845dbbfb-jxfqf.oregon-a.mozit.cloud
Date:
Sun, 22 Mar 2020 01:30:42 GMT
X-Frame-Options:
DENY
Content-Type:
text/html; charset=utf-8
Response Body



  
  



<!DOCTYPE html>
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      <meta name="description" content="Network administrators may configure their networks to modify DNS requests for the following special-purpose domain called a &#39;&#39;canary domain&#39;&#39;."/>
    
  

  
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Read more about our custom configuration and use of Google Analytics here:
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      data-media-url="https://user-media-prod-cdn.itsre-sumo.mozilla.net/"
      
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data-track-url="https://static-media-prod-cdn.itsre-sumo.mozilla.net/static/img/pixel.gif" data-document-id="46296" data-default-slug="canary-domain-use-application-dnsnet" >



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      <h1 class="title">Canary domain - use-application-dns.net</h1>
      
  
  
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      <p>To signal that their local DNS resolver implements special features that make the network unsuitable for DoH, network administrators may configure their networks to modify DNS requests for the following special-purpose domain called a <strong>canary domain</strong>: <strong><a href="http://use-application-dns.net">use-application-dns.net</a></strong>. 
</p>
<div class="note"><strong>Note:</strong> The canary domain only applies to users who have DoH enabled as the default option. It <strong>does not apply</strong> for users who have made the choice to turn on DoH by themselves.</div>
<p><br>
Firefox will attempt to resolve this domain using the DNS server(s) configured in the operating system of the device, and examine the result. The result will be considered negative if:
</p>
<ul><li>A response code other than NOERROR is returned, such as NXDOMAIN (non-existent domain) or SERVFAIL
</li><li>A NOERROR response code is returned, but contains neither A nor AAAA records
</li></ul>
<p>The result will be considered positive if:
</p>
<ul><li>The query completes with NOERROR and contains A or AAAA records (or both)
</li></ul>
<p>A negative result will be a signal to disable application DNS, i.e. DoH.
</p><p>The use of this domain is specified by Mozilla, as a limited-time measure until a method for signaling the presence of DNS-based content filtering is defined and adopted by an Internet standards body.
</p>
<div class="note"><strong>Note:</strong> Some existing DNS filtering providers implement similar domains for users to verify that filtering is working. This canary domain differs by being intended to be checked by software such as Firefox, rather than checked explicitly by the user, and by working across filtering providers.</div>
    
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