Speaking of Standards

Looking for a softphone that lets you easily make VoIP calls over IPv6 using the SIP protocol? I was looking to do this and after trying several of the common SIP softphones I knew of, several people pointed me over to Linphone which turns out to work like a charm! I knew of Linphone from a number of years back, but I mistakenly thought it was Linux-only… nope! It truly is cross-platform with binary versions for Windows and Mac OS X, and source available for Linux distros – plus versions for iPhone, Android and Blackberry.

With really just one configuration change, here is what it looked like to make a SIP call using IPv6 addresses (well, almost what it looked like since I did mask the actual addresses, being as security-paranoid as I am):

In the top address field I simply entered the SIP address using the standard format:

sip:user@ipddress

with the exception that because it is an IPv6 address I enclosed the address in square brackets (per RFC 3986). That’s it. I was off and making my call.

The One Configuration Step (and the caveat)

All I had to do to make this work was go into the settings (which you get by going to the “Windows” menu and choosing “Preferences” on Mac OS X) and checking off the box that says to use IPv6:

After checking that box and pressing “Done”, Linphone changed my identity to show my local IPv6 address and let me start making calls to IPv6 addresses.

The caveat

Now whether this “just works” does depend upon how you are connected via IPv6.

In my case, I use Tunnelbroker.net to have IPv6 in my home office (which I explained previously how to configure for Apple devices and for generic devices). The effect of doing this is that…

I am directly connected to the IPv6 side of the Internet.

So for me, the screen above with the radio button next to “Direct connection to the Internet” works fine. If you are behind a IPv6 NAT or gateway device, you may need to adjust the settings here.

Indeed, when I used Linphone for testing with IPv4, I did need to change the options myself, because for IPv4, my home network is behind a NAT / firewall. In my case I went for the second of the three options and provided my external IP address:

So you may need to adjust these settings in order to have Linphone work with IPv6.

Now, Linphone is a pretty bare-bones SIP client… it doesn’t have all the features and frills of many of the other clients out there… but that’s okay… all I wanted to do was test out the ability to make calls using SIP over IPv6. And for that it worked great!

As a bonus, it does not require you to set up a SIP account and register with a SIP registrar. You can just use it for direct computer-to-computer calling… which again is exactly what I needed in this case.

I’ll be writing more about making SIP calls over IPv6 in the weeks and months ahead… but in the meantime I thought I’d pass along this info.

I’ve tried Jitsi, the rebranded “SIP Communicator”, but it seemed to require me to set up a SIP account before I could make calls… and I don’t have an IPv6-compliant SIP system to which I can register.

In any event, I’m greatly impressed with Linphone… kudos to the team there for making it work so well over IPv6!

P.S. Thanks to some Voxeo colleagues for the recommendation of Linphone and also to someone in the #ipv6 IRC channel on Freenode (mentioned in this post).

Related posts:

1. Free Training on IPv6, SIP and Communications Apps – May 5, 2011
2. New IPv6 Mailing List From SIP Forum For Discussing SIP/VoIP Issues With IPv6
3. Want to learn about IPv6 and VoIP? Join the VUC Conf Call this Friday!
4. Will You Join In Olle’s Crusade for VoIP and IPv6?
5. Slides from eComm 2011: How IPv6 Will Kill Telecom – And What We Need To Do About It

Tags: IPv6, SIP, VoIP

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