Is anyone else having problems with a changing IP address?

mrc3 wrote:

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.  
 

Its not just NAT or CGNAT, its 464XLAT. Meaning your device is actually assigned a real IPv6 address, and issued an IPv4 IP only at the tower's edge. When you make an outbound connection, a WAN IPv4 address is assigned and translated via your IPv6 connection. This has the effect of an IP NAT pool, but not for the same reasons. A case-study was released where T-mobile claimed to do this as a result of IPv4 exhaustion causing deployment issues. This is more likely a side effect of the exhaustion of IPv4 than a sign of T-Mobile arrogance. Failure to communicate? Claro.

This means IPv4 traffic does not exist between the tower and the edge of T-Mobile network. It is all translated over IPv6. This is likely to become an increasing practice over time as IPv4 is finally phased out.

T-mobile does offer static translation (as Static IP Addon) to fix this issue, but only for business accounts. No clue why, either because T-Mobile literally doesn't have the 2 million IPv4s needed to handle the 2.0 million new home internet lines added in 2022, or because it's existing systems can't support 2 million extra assignments.