Monday, June 25, 2012

M9 and Asterisk

Asterisk is the most popular open source PBX. There must be millions of Asterisk-based installations out there. When comparing Asterisk with other PBX from Cisco, Avaya, Mitel, or others, the thing that is most obvious to me is it level of interoperability that invited and still invites many manufacturers of devices and software to integrate with Asterisk. This is the counterpart of the closed system where the warranty ends if you bring your own device.

We see that many of the snom m9 devices are used in environments that use some kind of Asterisk. While snom has its own PBX snom ONE, snom devices are still highly interoperable with all kinds of PBX in the market. It makes a lot of sense for snom to make the interoperability with Asterisk as smooth as possible.

The m9 has a slightly different concept than the desktop phones: Instead of having a seemingly millions of different configuration options, it has one drop-down per identity that determined the interoperability mode with the used registrar. Instead of having to figure out how to set each option right for your installation, the m9 comes with a pre-programmed list of servers. When selecting Asterisk, a few things like ICE and presence publication are automatically disabled. So just select the right dropdown and you should be all set picking the right settings for Asterisk.
We even brainstormed what we can do to improve the interoperability with Asterisk, but not much came to our mind. Newer versions of Asterisk support TLS and SRTP; on the forums we saw some hiccups with long TCP packets that seem to be fixed with the latest Asterisk version. On the m9 side, it seems there is nothing else that we can do to make this work better.

One interesting development where the Asterisk and snom m9 combination could become interesting is IPv6. Both Asterisk and the snom m9 are on the leading edge when it comes to IPv6. I personally know about an Asterisk snom m9 IPv6 deployment; it seems that this is working well.

When it comes to Asterisk interoperability, it seems that the m9 is in a good shape and we are running out of ideas what to do next. Improvements are more of a general nature that applies to all PBX systems. If anybody has an idea how the Asterisk integration can be improved, it would be interesting to get that feedback.

Thursday, June 14, 2012

Another IPv6 Day

On June 6th, there was another IPv6 day. As the snom m9 is one of the few devices that I know of which supports IPv6, that day was a special day for us. We know that a few folks are using IPv6 with the m9, but honestly it would be great to get more feedback if we are done with the IPv6 support.

It seems the biggest change was that Google added an AAAA record for the email server address. That screwed a lot of email clients up, and I am not sure if Google kept the records or just had set a very long TTL, so that the problem did not go away on the next day. Actually, if the m9 would have been exposed to IPv6 and the SIP server also supports IPv6, the transition should have been very smooth. The user should not have even noticed it. I don’t believe many m9 users actually had that experience.
My biggest concern is that the firewall manufacturers will advertise NAT as a security feature also for IPv6 and the purchase departments are too clueless to find out that this is nonsense. The idea of a 50 USD router with the IPv6-ready logo sticker on the gift box scares me. Probably we only have to wait until some smart-ass lawyer sues a router manufacturer because they exposed “private” IPv6 address to the public, and a badly configured PC in the LAN gets hacked (that’s why we have stickers on the microwave telling us not to put mister hamster into the device). Then all legal departments of the router manufacturers in the world will take over and mandate that addresses in the LAN are not exposed to the public, evil internet. I even hear that they are now trying to put that functionality into the Linux kernel, so they say, to make sure that at least the NAT implementation is not as buggy as with IPv4. If that should happen, the whole exercise with IPv6 was for nothing and we will still associate VoIP with on way audio: Can you hear me? Maybe not hearing the other side is a security feature, for some people. Not for me.