@dashrender you could see opensips as a software version of this, but in high load scenarios or in transcoding the example @scottalanmiller gives about restricted instruction sets on the video chip is a great example.
If Asterisk was created after SIP standards were made it probably would have some type of domain filtering that would make the mobile issue a very easy fix.
That being said the responsive firewall was a huge leap forward, but i don’t see anything in their big requests that indicates they are going to go further. I’ve not tried to use the Sangoma SBC or to fix the issue since I’ve moved on. I’m guessing the domain for mobile access is very low amongst FreePBX users, or maybe it’s used on desktops inside a LAN that is not using the responsive firewall.