October 2012 archive

Today’s VUC Call – Setting Up A Cellular Network In The Desert For Burning Man

TimpantonToday's VoIP Users Conference (VUC) call at 12:00 noon US Eastern should be quite an interesting one. Tim Panton from Voxeo Labs and Tropo will be joining the call to talk about his experience setting up a mobile network in the middle of the desert for this year's Burning Man event.

Tim recently described the experience in a guest post at TechCrunch: "What We Learned Running A Mobile Network At Burning Man" and on the VUC call will talk more about what he did. The FAQ from the Papa Legba camp at Burning Man makes for quite an interesting read. I'm looking forward to hearing more from Tim... and the call is open for anyone to join in.

You can join the live call via SIP, Skype or the regular old PSTN. There is also an IRC backchannel that gets heavy usage during the call. It will be recorded so you can always listen later.

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DANE Test Sites

The following sites support the DANE protocol by publishing TLSA records. If you are developing software that supports the DANE protocol, you can visit these sites to test your DANE support.  Note that we use the term “TLS certificate” here for what is commonly referred to as a “SSL certificate”.

 HTTP – Valid TLSA Record With Valid CA-signed TLS Certificate

The following sites use a valid CA-signed TLS certificate, but the CA is CAcert, a free CA that is not commonly configured in web browsers:

The following site has a valid TLSA record and a valid CA-signed TLS certificate, but the domain is not tied into the global DNSSEC chain-of-trust, i.e. there is no DS record for huque.com in the .COM TLD:

HTTP – Valid TLSA Record With Valid Self-signed TLS Certificate

HTTP – Valid TLSA Record With Invalid CA-signed TLS Certificate

HTTP – Invalid (Broken) TLSA Record

HTTP – Valid TLSA Record With Invalid DNSSEC Signature


The following sites support using DANE for email by publishing TLSA records associated with MX records:

  • jhcloos.com
  • nlnetlabs.nl (for ports 25, 465, 587)
  • nlnet.nl (for ports 25, 465, 587)

XMPP / Jabber

The following sites support using DANE for TLS connections to their XMPP/Jabber server:

  • jabber.nlnetlabs.nl

Adding More Sites

If you support DANE with your site and would like to add it to this list, please contact us. Eventually, of course, we would like to hope that DANE is so widely deployed that this list of test sites will no longer be needed.

RFC 6698 – The DNS-Based Authentication of Named Entities

For anyone interested in how to better secure the Internet, the DANE protocol (“DNS-Based Authentication of Named Entities“) provides a mechanism for using DNSSEC to specify precisely which SSL/TLS certificate you want people to use to connect to your web server or other Internet service.  This provides a mechanism for ensuring that you are in fact using the correct certificate and your connection is not being intercepted by anyone in your network path.  DANE is defined in RFC 6698 at:

The abstract is:

Encrypted communication on the Internet often uses Transport Layer Security (TLS), which depends on third parties to certify the keys used. This document improves on that situation by enabling the administrators of domain names to specify the keys used in that domain’s TLS servers. This requires matching improvements in TLS client software, but no change in TLS server software.

Please view our page on the DANE protocol for more information about how the protocol can be used and how it helps make the Internet more secure.

The DANE Protocol – DNS-Based Authentication of Named Entities

If you connect to a website using a “secure” connection over TLS/SSL, how do you know you are using the correct TLS/SSL certificate?

You may see the “lock” icon in your web browser, but are you sure that you are connecting all the way to the website using the correct TLS certificate?  It is in fact quite possible – and quite common – for a firewall or other device in your network path to terminate your TLS connection with a website and then re-create a TLS connection from the device to your browser.  You think you have a secure, encrypted connection to your bank, for instance, but in fact your connection has been intercepted and the firewall or other device is able to see, and potentially record, all your interaction with the web site.

With DNSSEC now being deployed, a new protocol has emerged called “DANE” (“DNS-Based Authentication of Named Entities“) that allows you to securely specify exactly which TLS/SSL certificate a browser should use to connect to your site.  If a web browser supporting DANE detects that it is NOT using the specified certificate, it can warn you that your connection is insecure… even though you see a “lock” icon.

DANE is defined in RFC 6698 and over the next few months we will be adding more tutorials and document to this site to help you understand both how DANE helps make the Internet more secure and also how you can get started either publishing TLSA records for your domain – or using DANE within your application.  Note that DANE is not just for websites. People are already looking at how DANE can be used to secure email, VoIP and other web services.

For an explanation of the DANE protocol, watch this interview with Warren Kumari, co-chair of the DANE Working Group within the IETF:

[Additional screencast to be inserted here explaining how DANE works.]

Another good introduction to DANE is an IETF Journal article published in October 2011 titled “DANE: Taking TLS Authentication to the Next Level Using DNSSEC“. In the article, Richard Barnes explains why DANE is needed, outlines how it works, digs into some of the challenges with DANE implementation and provides a good number of links for more information.

Content Providers

[This section will explain to website owners/operators and providers of other services how they can publish TLSA records to make their sites more secure.]

Application Developers

The following libraries are in the process of adding support for the DANE protocol:

  • dnspython – the development version of dnspython found on Github has had support for TLSA records added to the code base. This is not yet available in a formal release.
  • ldns – an upcoming release of ldns will provide support for DANE (this page will be updated when the release occurs).

Other resources for developers:

  • DANE Test Sites – If you are adding DANE support to your application and wish to test out how well it works, the sites on this page are early supporters of the protocol and can be used in your testing.

Getting More Involved

If you would like to get more involved in the development of the DANE protocol and supporting documentation, you can:

How Do We Measure DNSSEC Deployment?

Map of DNSSEC-validating usersHow do we measure the actual deployment of DNSSEC?  How can we know how many domain name holders have signed their zones with DNSSEC? How can we find out how many ISPs have deployed DNSSEC-validating resolvers? How do we count how many applications or operating systems have built-in support for DNSSEC validation?

At first glance, some of these would appear to be simple questions to answer – “well, can’t you just count up the number of DS records in a top-level domain?” But the reality is that it’s not quite that simple.  There are sites providing DNSSEC deployment statistics and some TLDs are making DNSSEC usage available… but that’s not true across the board.  And the validation question is quite difficult due to the distributed and decentralized nature of the Internet.  We recently wrote about some work Verisign Labs is undertaking to measure validation, but that work is just beginning.

The APNIC Experiment

So we were delighted to see the post, “Counting DNSSEC” and accompanying presentation from Geoff Huston and George Michaelson at APNIC Labs where they dug into this DNSSEC measurement issue in a unique way.  As Geoff writes, they set out to look at these questions:

  • How many zones are DNSSEC signed?
  • How many DNS queries are DNSSEC-validated?
  • How many DNS resolvers are DNSSEC-capable?
  • How many users are using DNSSEC-aware DNS resolvers?

But rapidly concluded that these precise questions were difficult to answer – and so they decided to look a bit more broadly at these questions:

  • What proportion of DNS resolvers are DNSSEC-capable?
  • What proportion of users are using DNSSEC-validating DNS resolvers?
  • Where are these users?

Their measurement technique was to use advertisements in web browsers displayed through an advertising network.  They used a flash-based ad that made multiple DNS requests without user intervention, i.e. the user didn’t have to click on the ad – just the action of displaying the ad triggered the measurements.

They ran the test from September 10-17, 2012, and observed 57,268 unique IP addresses requesting the DNS records. Some of the conclusions were interesting:

  • 4% of DNS resolvers performed DNSSEC validation
  • 9% of end-client systems were using a DNSSEC-validating resolver

Their post goes through all this in great detail and provides a much more thorough explanation than I can do here.

They then went on to look at where the users were coming from and provide charts segmenting their data in multiple different ways.   They summarized all of this in a presentation to the recent RIPE 65 event complete with charts showing the validation by country.  I’d highly recommend you take a look at that presentation as it provides an excellent view into all this data.

As with any survey like this, you can always wonder about the distribution of people seeing the displayed ad. My first thought was that as I browse with Flash disabled by default I would never have triggered their measurement had it been displayed on my screen.  Similarly many mobile devices might not execute Flash, notably Apple devices, and so it would miss those users.

But even with those caveats, this is an excellent piece of work as an attempt to perform some basic measurements.  Geoff notes at the end of the post that they’ll perform another look at DNSSEC deployment in a few months time, and we’re very much looking forward to seeing what difference they’ll measure in that next look.

What Else Can Be Done?

Beyond this work, we are still thinking a great bit about what else can be measured.  For instance, can we as an industry develop:

  • a count of registrars supporting DNSSEC by allowing upload of DS records?
  • a count (or %) of DNS hosting providers providing automated DNSSEC signing?
  • a % of ISPs providing validating name servers?
  • a % of signed second-level domains?

On this last point, there are great examples already out there including the PowerDNS stats for .NL and other domains, the Verisign Labs scoreboard for .COM/.NET/.EDU and the NIST statistics for the US Gov’t and industry, but it would be even better if we could aggregate this information and also obtain that information for other TLDs.

How can we best measure the deployment of DNSSEC?  It’s an interesting question… do you have any thoughts about other methods and mechanisms?


Slides: How The Hidden Secret of TCP/IP Affects Real-time Communications

Recently at Voip2day + ElastixWorld in Madrid 2012, Olle E Johansson gave a great presentation outlining where we are at with telecom and VoIP in 2012 - and where we need to go! Olle is a long-time, passionate and tireless advocate for the open Internet, IPv6, SIP and standards and interoperability. I've known Olle for years via Asterisk-related issues, via the VUC calls and via work on SIP over IPv6.

This presentation (slides available) really hits a number of key points about where we are at now:

In particular I was struck by his slides 24-28 that strike the same theme I've been writing about across multiple blogs, namely the way we are reversing the "open Internet" trend and retreating back inside walled gardens of messaging:

This is what customers wanted to avoid

He goes on to walk through what happened with SIP and how the protocol evolved - and evolved away from interoperability. His conclusion is that we as customers need to take back control, avoid vendor lock-in and demand interoperability.

He also points people over to his "SIP 2012" effort where he is undertaking to compile a list of what really defines "SIP" in 2012, i.e. more than just RFC 3261. (I'll note he's looking for feedback on these ideas.)

All in all an excellent presentation... and yes indeed we all collectively do need to "WAKE UP" and demand better solutions!

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Video from CO ISOC: IPv6: What is it, why do I need it, and how do I get it?

What is IPv6 all about? Why do you need it? How do you get it? These are the questions a recent event hosted by the Colorado (US) chapter of the Internet Society on August 28, 2012, sought to answer. The session began with a keynote by Scott Hogg, Director,Technology Solutions, Global Technology Resources (GTRI) and then was followed by a panel including:

  • Jeff Doyle, President, Jeff Doyle and Associates
  • Chris Grundemann, Network Architect, CableLabs
  • Cricket Liu, VP, Architecture & Technology,Infoblox
  • Shannon McFarland, Principal Engineer, Corporate Consulting Engineering Group, Cisco
  • Scott Hogg, Director,Technology Solutions, Global Technology Resources (GTRI)

More information and bios of the presenters can be found at: https://coisocipv6.eventbrite.com/

The session itself is available on YouTube and comes in around 1 hour and 46 minutes:

FIR #671 – 10/01/12 – For Immediate Release

Three speeches and an interview are up; no Asia report this week; Quick News: HootSuite introduces internal feature, Quartz magazine launches, Kellogg's swaps snacks for tweets, Twitter launches header image; Ragan promo; News That Fits: CEOs still fearful of social media, activists use Amazon reviews to undermine book, CustomScoop promo, listener comments, Dan York's report, TemboSocial promo, Klout scores for hiring decisions are stupid, answers to Quora question about PR and social media; music from Lit on the Flash; and more.