In the next release of one of our core PBX engines SRV DNS record resolution appears to be disabled. A new field called "Alternative Proxy" in version 16 has appeared.

Failure to remove the SRV entry when upgrading to version 16 results in the server being unable to connect to the trunk account. If you are already using a non SRV record for registration, no changes are required to your system, but you may still benefit from the guide. Please note that we had no input in this change.


Note: At the time this article was written, the newly updated version 16 does not have a working SRV template. If you are attempting to register to the SRV record such as or, your trunk will not register. All SIP traffic must be destined directly to the underlying registration server like,,, etc.


On the General tab of the trunk configuration, your 'Registrar/Server/Gateway' host should already be populated with the primary registration server such as ''. Under the Authentication section, enter your Trunk Number as the the Authentication ID and your Trunk Password as the Authentication Password. 




Select the 'Options' tab in the trunk configuration. Under 'Advanced', check 'Alternative Proxy' and enter the secondary registration server such as ''. This will enable failover to our redundant gateway if the zombie apocalypse begins in Atlanta and is taken down. 


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Select the 'Inbound Parameters' tab in the trunk configuration. Change the 'CalledNum' parameter from 'To: User Part' to 'Request-Line URI: User Part'. Click OK to save the trunk configuration.



If you have any questions on this please don't hesitate to contact bvoip support