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Failover server, not working properly with Identity failover


I'm having a hard time with the failover server. Was never able to get it to work properly. I don't think the way it's currently done, is intuitive, and even harder to provision and program. DNSSrv is even more annoying to setup because not all the manufacturers support it, or even implement it properly.

Using Yealink and Grandstream, it's extremely simple and straight forward. Simply put the backup IP and if the main server goes offline, then it automatically failovers to the backup server. 

Do you plan on implementing this type of setup? It is currently the only feature swaying us away from Snom sets. 

Currently, I'm updating the phones to This includes all the Snom 3xx and 7xx. I think the failover idea that is currently implemented is very poor compared to the rest of the other brands out there.

Any update? Are you planning on introducing this type of failover? Or the second identity process?

Hello Chris,

with version 10 (

we deliver / address what you mention in your intro: "DNSSrv is even more annoying to setup because not all the manufacturers support it, or even implement it properly."

There was plenty of room for improvement, regarding this NAPTR and SRV DNS records based failover support, - no question. We are convinced we recently nailed it:

@Snom we did spent a lot of efforts & expertise in proper implementation & support of this in many ways carrier grade failover (where 2 nodes support is not worth a mention).

Finally our support for NAPTR and SRV DNS records failover in Version 10 is approved by a minimum of 3 major European carriers, operating multiple 10k of our phones.

- - -

But I agree, that the simple and straight forward active & backup server scenario has it's value and importance depending on the project needs.

Personally, I am inclined to at least discuss and "challenge" this topic internally with our team on next opportunity.

Will try to provide a response regarding the result soon.

Note: please do understand that any improvements / new features etc. will only be implemented to Version 10, - limited to phone models supported on V10 respectively.

Thanks and greetings from Berlin,


Jan Boguslawski

Product Owner Snom

Hi Jan,

Any news on this matter?

Hi Chris,

we did not tried to follow the exact same path for a straight forward active & backup server setting implementation so far.

But we do support multiple outbound proxy configurations for failover scenarios, which potentially is sufficient and fairly easy to configure:

The setting  supports multi values for a while with comma as separator (for details please see Snom Service Hub):;transport=tls,;transport=tls,;transport=tls 

Please note: if user_outbound is specified, no matter one or multiple values the phones DNS resolution will skip any NAPTR or SRV discovery or try any later re-discovery attempts.

Lets say you have a primary IP and the backup IP you should be able to achive a working failover setup by:

<user_outbound idx="1" perm="">,</user_outbound>

(for provisioning via XML)

or inside the phone webinterface you could open the configuration for Identity 1 ( http://phone-IP-address/line_login.htm?l=1) and enter both server IP's comma separated into the  Outbound Proxy text field.

Hope that helps, at least for a reproduction attempt / test-run. Looking forward to your feedback.

Thanks and greetings from Berlin,


Jan Boguslawski

Product Owner Snom

That could work! Has this feature been added to the newer firmware (10.x) or it's always been an option even in previous firmware (if so, when was it included?) 

Also, does the take the outbound values sequentially? ie: take the first value, then the second only if the first failed...?

Thank you

Hi Chris,

the featue was already introduced in early versions 8.7.x. It was not clearly explained in our old Wiki or the new Snom Service Hub, but the Valid Value is indicating it indirectly.

I added now additional clarification the description in

which includes the answer to your second question: yes , entries are taken sequentially.

Please note: I had no chance to test it with most recent FW or older FW, - but it should still work as expected (as it is used by several Snom key partners in Hosted Voip/Cloud PBX, with 8.9.3x or V 10.x).

Thanks and greetings from Berlin,


Jan Boguslawski

Product Owner Snom

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