Is anyone else having problems with a changing IP address?

t-mobile loves to blame this as normal dynamic IP address assignment which it is NOT.   The IP address of traffic leaving your gateway (house) is NOT really changing (well it is changing as often as it normally does with dynamic ip assignment, which is rarely).  

As evidence, if your gateway IP address changes, every existing connection will be terminated.  Downloads, video streams, chat connections, etc.  this is not happening.  

What is happening is that a device within t-mobile is doing NAT (network address translation) and using a different source address for every new connection to a different destination IP address.  IT SHOULD NOT BE DOING THIS as it causes problems like this, especially with cloud based servers where the a given DNS host name has multiple IP addresses. The NAT device needs to disregard the destination address in it's NAT lookup for new connection attempts.  

This is best demonstrated using a phone (which has the same problem on t-mobile as the gateways)… But the phone allows you to see the IP addresses assigned to your device.   Using your phones web browser, go to a website which reports your IP address… note that it DOES NOT match your phones IP address.  This is because of the translation that is taking place.  Note you may have two IP addresses assigned and IPV6 address and an IPV4 address.

There is another way of demonstrating this problem using multiple sites that report IP address of your connection, but that is less reliable.

This is an internal practice of t-mobile that appears to be related the Minneapolis Geography and breaks internet conventions and assumptions used by many servers.  Maybe someday somebody will get high enough up into the t-mobile engineering team to reach somebody who understand the technology and equipment that they use and correct the issue.

Mike