SIP Protocol Transmissions on port numbers 5060 or 5061


    T-Mobiles network is not a truly open network. Because since early Dec 1016 when t-mobile pushed out firmware 27.1 to all iphone users along with iOS 10.2 ALL SIP softphone apps that use TCP or UDP on port numbers 5060 or 5061 to connect to SIP servers and other SIP endpoints no longer work on their network.


    I've tested this on 6 different iphone all using firmware 27.1 , 27.2 and even the latest beta 27.5 and none of them work on t-Mobile. I've tested the same application on verizon, sprint and att phones and everything works fine on their network.


    I've been calling and trying to work this out with t-Mobile technical support team for over a month now and they seem completely clueless.

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