MultiWan and Wifi Calling
-
I have a multiwan setup that does simple fail-over. When my primary connection fails everything on the network works through the secondary connection perfectly with one exception. I am in an area with no cell service so I depend on WiFi calling for service. When the primary connection is working - wifi calling works perfectly - when the primary connection fails, wifi calling ceases to work until the primary connection is re-established. My sip connections to VOIP trunks work fine - it is just wifi calling from the cell phones that fails. To further complicate the issue - texts via wifi continue to work. I am sure it is probably some type of static port mapping issue, but I have reviewed everything in the setup I can think of without discovering a problem. The real issue is that my knowledge of how wifi calling works between the phone and the carrier is deficient - I've of course asked the carrier for technical details to a resounding silence. Searching the web generates lots of guides on how to activate it but nothing I can find that explains the protocols involved. Any ideas where I should be looking to resolve?
-
@kitdavis Hey, Kit, if your backup has a smaller MTU (e.g. DSL) make sure to set MTU/MSS on the interface. I ran into this with a TMobile 4G Home Internet box which has a 1420-MTU due to their 464XLAT encapsulation, and it straight-up broke WiFi calling not having the MTU set low enough.
I thought it was pfSense due to several messages here, but when helping out a friend with pfSense vanilla everything on a Spectrum cable connection it worked perfectly so I took a closer look.
2.6.0 in both locations.
