WI-FI Calling on Linksys

You can see if anyone here solved this problem, but since the problem seems to come from your new router, with the due respect, I would suggest that you post your question to the appropriate forum:--> https://community.linksys.com/?category.id=English

Thanks and regards

Giulio

Those ports are not Apple specific though. Those ports are used with all carriers for all WiFi calling. On any consumer router, there is no reason for UDP 500 and 4500 to be blocked by default in the first place, so not sure why they would be on your Linksys. Nobody should have to do anything with their default consumer router for WiFi calling other than enable WiFi calling on their cell phone. My netgear and current ASUS AC5300 just worked for AT&T WiFi calling - I did nothing to configure them for it.

You should also have TCP 143 open, according to AT&T’s forum support, but again, it shouldn’t be blocked by default anyway.

In the Linksys community forums though it does seem people have issues with Linksys routers? Have you searched Linksys’ own community forums - a web search comes up with several posts about it, although from what I see, not everybody is able to resolved it.