We recently updated to new WAN interfaces at two of our locations. We use @Skyetel SIP trunks at both sites. From the Skyetel portal, I added the IP addresses of the new interfaces to the appropriate IP groups, and the health in the Skyetel portal is showing ok for both.
I disabled the old WAN port at location 1 and all SIP trunks continued to work as before with no issues.
I disabled the old WAN port at location 2 and SIP is not working. The calls are completing, both inbound and outbound, but there is no audio from either direction. I re-enabled the old WAN port and call audio immediately resumed.
My takeaway from that is that the SIP messages are correctly using the new interface, but the RTP streams are not. They seem to still be using the old interface. Is there a setting in either Skyetel or FreePBX that sets what interface the RTP streams use? I always thought that they would use the same interface that the SIP messages were using and I don't remember having to set anything specific for RTP when these sites were set up other than firewall rules for the associated port range.