I have an AT&T M-Cell. It seems to want to use port 4500 UDP, but I see that other devices besides that M-Cell are able to use that port at the same time. I have an enforced outbound policy by Source IP for port 4500 UDP for WAN2, yet I have seen this device with its connection on WAN1. I have now set the enforced policy to just Source IP, and I continue to find this M-Cell device with an Active session from it to the internet on WAN1. How is that happening?
Whatever is going on is possibly causing dropped calls on my cellular. The M-Cell is a local cellular access point if you will. My house sits between two cellular towers and my phone constantly bounces from one to the other - which destroys my battery. The M-Cell maintains a strong enough signal to keep my phone from ever searching for another network.
Yes, the iPhone has Wifi calling, but it is programmed to prefer cellular. It will scan for cellular even while on Wifi for calling. When the M-cell connection craps out - it switches to Wifi calling - but it also wants to use UDP port 4500 - what is so sacred about this port? Why can’t I manage it like other ports?