We are trying to figure out DDNS and how to implement it for failover for SIP trunks.
I tested with our provider ESI on two different systems.
Here is how I set it up, on both systems.
Enabled DDNS in System Admin Pro, got correct external IP
Went to Asterisk SIP settings Put into General and Chan_SIp settings the DDNS url in the External IP , left the Type of IP the same at static. Applied Config. Made test calls. On my system the calls went OUT fine, On the customers system the call was rejected by ESI. I did a TCPdump and found out that the failed call was sending the internal LAN IP of the phone system.
Here is the system info for both:
My system.
Fpbx 10.13.66.17
Sys Admin Pro 13.0.74.14
Customer system
Fpbx 10.13.66.20
Sys Admin Pro 13.0.75.3