TMobile Gateway IP Addresses

The T-Mobile gateways do have a DHCP server which is set with the fixed gateway IP of 192.168.12.1 and the network mask of /24 for the Class C, IP network. The DHCP scope appears to be from 101-254 and the gateway address is excluded. Some users do connect an additional wireless router and double NAT just to have additional local network controls and features. Devices that do connect to the wireless or Ethernet network directly via the available gateway resource are restricted to the 192.168.12.X/24 network. There are workarounds for ways of communicating across the 464XLAT environment but of course it all comes with a cost. 

T-Mobile does run 464XLAT and they leverage IPv4 and IPv6 so there are some limitations for port forwarding with the technology. It is a move toward support for IPv6 and migration as IPv4 addresses are in short supply now and the cost to obtain IPv4 addresses is prohibitive. The use of IPv6 provides the enormous pool of available addresses and given the explosion of internet connected devices moving forward with IPv6 is really the most cost effective solution. As more hardware and software developers provide IPv6 vs IPv4 for content delivery many limitations imposed by the prior paradigm for IP communication could be resolved. It will be years before the industry moves forward with applications that embrace the future requirements. It is pretty much like people still having ICE vehicles due to the infrastructure and the cost of electrification of vehicles and the enormous costs associated with making the move to build out support infrastructure to make it happen. Cost is a big factor period.

User email in/out from the local LAN works. If there is content filtering taking place then that is a different issue. I have used Windows, Apple, and Linux clients for email service/delivery and it seems to work fine for me. 

T-Mobile has pushed to be innovative and push forward with the 5G cellular internet delivery. They provide the service at a lesser cost than "some" big ISPs and do it without contracts, extra hidden fees, and they don't even force the new subscriber to buy the gateway nor add hidden connection fees and etc… plus the cost is not going up every year or at a renewal period. Is it perfect? No. In some environments the delivery is very good. Cellular communication has some limitations for some locations as there are many external factors to contend with. I don't work for T-Mobile. I am just a user since January 2021 and I have seen some glitches here and there but service from the 5G cellular solution with T-Mobile is much faster and more reliable than the provider we had using DSL which was more expensive and much, much lower bandwidth. If the T-Mobile cellular solution does not fit for you go find internet nirvana and be happy. Life is short.