Deploy360 1 February 2014

Weekend Project: Install The DNSSEC/TLSA Validator for Chrome, Firefox, more

By Dan YorkDirector, Internet Technology

DNSSEC / TLSA ValidatorHow do you know if a website has a domain signed by DNSSEC?  Here’s another quick weekend project, very similar to last weekend’s project , where you can add support to your web browsers to know the DNSSEC status of sites you are visiting.  Even better, as people start to use the DANE protocol to secure TLS/SSL certificates, you’ll be able to know when DANE is being use.

The great team at CZ.NIC Labs has released a new version 2.1 of their plugin for Google Chrome, Mozilla Firefox, Microsoft Internet Explorer and Opera.  You can get it at:

A key difference in this version from previous versions is that it now has support for the TLSA record in DNS that is used by the DANE protocol to add an extra layer of trust to the usage of TLS/SSL certificates.

Once you have the DNSSEC/TLSA validator installed in your browser, you should be able to go to links on these pages to test out your new capabilities:

When you visit the sites, you should see additional icons in your browser’s address bar that will give you information such as this:


The addition of TLSA record support is a great new feature!  While TLSA record usage is still quite small among web sites today, having this ability to see the TLSA usage will definitely help the people out there who are pioneering the usage.

Kudos to the CZ.NIC team for making this available!

P.S. Do note that in order for this to work in your web browser needs to have access to a DNSSEC-validating DNS resolver.   [UPDATE: As noted in the comments to this post, the add-on no longer requires access to a DNSSEC-validating DNS resolver. The required capabilities were built into the code instead.  Having said that, it’s still also great to make sure your local DNS resolver does do DNSSEC validation for all the other apps you have.] The add-on can use DNSSEC-validating DNS resolvers from CZ.NIC or Google, buy why not make your network that much more secure and install your own DNSSEC-validating resolvers?  Check out our recent weekend project to learn more about how to configure DNSSEC validation on your local DNS resolver.

Disclaimer: Viewpoints expressed in this post are those of the author and may or may not reflect official Internet Society positions.

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