April 13, 2012 archive

Apr 13

Jitsi Is The First VoIP Softphone To Support DNSSEC

JitsiWith it’s 1.0 release last week, the Jitsi soft phone became the first VoIP client I know of to support DNSSEC. Jitsi, formerly known as the “SIP Communicator”, is available for Windows, Mac OS X or Linux from:

jitsi.org

Jitsi has a great range of features including support for voice and video calls, chat/IM, desktop sharing, conference calls, wideband audio and much more. It works with the SIP (Session Initiation Protocol) and XMPP (Jabber) protocols and connects to common services like GoogleTalk, AIM, Yahoo!Messenger, Facebook chat, etc.  It’s also free and the source code is all available.

Jitsi has supported SIP and XMPP over IPv6 for quite some time now, but with this new release adds support of DNSSEC courtesy, I learned, of some funding from the NLnet Foundation and the University of Applied Sciences and Arts Northwestern Switzerland (FHNW). The DNSSEC code itself was implemented by Ingo Bauersachs from this university.

Essentially what Jitsi now does if you enable DNSSEC is to validate the signing of the SRV records in DNS that provide the address information for the remote end of the SIP or XMPP connection.

To step back and explain a bit further, if Alice wants to call Bob (to be cliche), and she knows his SIP address is “sip:bob@example.com”, her SIP client, IP-PBX or other SIP server (depending upon configuration) is going to perform a DNS lookup on “example.com” to retrieve the relevant SRV records. These records will provide the IP address(es) of the SIP server on Bob’s side. Alice’s SIP software will then connect to those IP addresses to send the appropriate SIP INVITE to start a conversation with Bob.

But how does Alice’s software know that the SRV records retrieved from DNS are correct? How can it know that they were not tampered with?

What if she is trying to call her bank and an attacker is redirecting her to another SIP server where there is a similar call center or IVR? (Okay, leaving aside the fact that at this moment you may not be able to make SIP connections to many banks… but that is changing slowly.)

Enter DNSSEC.

If the “example.com” domain is signed via DNSSEC, including all the SRV records, then the VoIP client can validate that the SRV records are in fact correct and the connection can be made knowing that it is to the intended recipient based on the SIP address.

From a configuration point of view, there has been one more screen added to Jitsi’s preferences:

Jitsi dnssec

At this moment there is no documentation on the Jitsi site about the DNSSEC features (they are working on it… and open to any offers of assistance! ;-) , but I asked Ingo Bauersachs about the configuration of the resolver. His reply was this:

Libunbound, the library Jitsi is using, is validating the DNSSEC chain, but it’s not a full resolver. Queries for DNSKEY, DS, etc. are sent to the OS’s resolver, or if configured, to the “Custom name servers”.

The option to override the OS’s default resolver is there because during development, the only servers supporting all relevant record types were from DNS-OARC and Verisign.

The choice not to use libunbound as a fully recursive resolver was performance and that it’s for one simply not the job of an application to perform recursive DNS queries.

In my own case, I’m running a local instance of DNSSEC-Trigger and that is my operating systems default resolver. I’ll be able to perform the DNSSEC resolution without any issues. Ingo also indicated that the table at the bottom of the Preferences panel will fill up with domains as you start to connect to sites (any sites – DNSSEC-signed or not). You can then specify what the DNSSEC-related behavior is for individual domains.

That’s how this all works, of course, when you have both publicly accessible SIP servers with SRV records – and DNSSEC signatures on those records. There may not be a whole lot of those sites out there quite yet, but having apps like Jitsi available will only help.

If you have a SIP- or XMPP-based VoIP or IM system (or “Unified Communications” system to use the appropriate marketing buzzwords) where you can sign your domain with DNSSEC, definitely check out Jitsi and see how it works. And as you have it working, I’d certainly love to hear from you and perhaps feature some examples in future blog posts.

The Jitsi team is also very interested in feedback and indicated that sending messages to the “dev” mailing list (and joining that list if you want) would be the best way to proceed.

I’m also personally interested in trying this out in a test environment… if you’ve got a SIP server with a domain that is DNSSEC-signed, please drop me a note as I’d like to try calling you. :-)

Kudos to the NLnet Foundation for funding this work and to Ingo Bauersachs and the Jitsi team for implementing it all. I’m looking forward to seeing where this goes!

P.S. Wikipedia has a decent page on SRV records if you want to know more about these record types.

Apr 13

Have You Signed Your Domain With DNSSEC Yet? (Here are instructions…)

Have you signed your domain name with DNSSEC yet?  If not, how about doing that today?  Or as a weekend project?

This one little step can go a long way in both helping make your own Internet presence that much more secure and also in helping move the overall DNSSEC effort forward industry-wide.

To help you out, we’ve put together a few “how to sign your domain name using DNSSEC” tutorials for some of the leading registrars supporting DNSSEC:

http://www.internetsociety.org/deploy360/resources/dnssec-registrars/

If your registrar is not listed on that page, you can also check ICANN’s list of registrars supporting DNSSEC to see if your registrar is listed.

If your registrar is not listed on either site, you may want to look at your registrar’s website to see if they have any mention of DNSSEC. Note that I’ve found a couple of registrars out there who mention “Premium DNS” and on closer inspection turn out to essentially be GoDaddy resellers – in which case the GoDaddy DNSSEC tutorial applies. (And if you do find that they support DNSSEC, could you please send us a note so that we can add them to our list? Thanks!)

And if you still can’t find any information, why not drop an email to your registrar’s support address asking when they will have DNSSEC support?  Either that… or consider moving your domain to a registrar that does support DNSSEC already!  (Yes, I know, moving registrars can be a headache… )

If we can each take a moment to go out and sign some more domains (or to encourage more registrars to support DNSSEC), we’ll move that much closer to having a more secure Internet!

Apr 13

WordPress Dominates Top 100 Blog/Media Sites

If you had any doubt about the outcome of the "platform wars" of the past few years for "blog"-type sites, one graphic can remove that doubt:

Wordpress top100blogs 201204

This comes from a just-released study from Pingdom and before you say "well, of course, this is all about blogs, so naturally WordPress would dominate"... please do scroll down the article and see the range of sites that Pingdom's study covers (the ones that are italicized use WordPress):

  • Huffington Post
  • Mashable
  • TechCrunch
  • Engadget
  • Gizmodo
  • Ars Technica
  • The Next Web
  • GigaOm
  • CNN Political Ticker
  • ReadWriteWeb

... and many more... the point is that what is classified as a "blog" for this study includes many of the "media" sites that many of us visit frequently - and many of those "media" sites turn out to be using WordPress.

The Pingdom article has many other great pieces of information, including this chart comparing the platforms of the Technorati Top 100 blogs in 2009 versus 2012:

Blog platforms

The outright (and not surprising) decline of some platforms like TypePad (on which this DisruptiveConversations site is still hosted) is very clear for all to see as well as the strong rise in WordPress usage.

The ecosystem around WordPress continues to expand at a phenomenal rate and studies like this are useful to measure that actual growth. What would be interesting to see, too, would be a study of "websites" in general, i.e. not just "blogs" but perhaps the Alexa Top 100 or some other set, to see what % of sites there use WordPress and these other platforms. As noted in the Pingdom article, the WordPress team has spent a great amount of time working on making the system more useful as a more generic content management system (CMS) and so the type of sites that are now using WordPress is expanding far beyond its roots in blogging. It will be interesting to see how that changes the web hosting dynamics over the next few years.

Thanks to Pingdom for undertaking the work - and I look forward to seeing what the field looks like in another three years!

If you found this post interesting or useful, please consider either:

Apr 13

Jima’s IPv6 TLD Hall-of-Shame

Patrick “Jima” Laughton is an advocate for IPv6 who, inspired by a conversation on Facebook, decided to do something to highlight which top-level domains (TLDs) were NOT IPv6-ready.  And thus was born the “IPv6 TLD Hall-of-Shame“, available at:

http://jima.tk/u/v6tlds

He has two lists:

  1. TLDs without IPv6 nameservers
  2. TLDs with IPv6 nameservers but no IPv6 “glue” records in the root zone

He’s been updating the list periodically and has been removing TLDs as they add IPv6 service. As World IPv6 Launch grows closer and closer, we’d like to see these lists shrink even more!

Kudos to Jima for creating and maintaining this list and we look forward to the day when he’ll have empty lists and can shut the site down.