T-Mobile Home Internet location jumps between cities: why it happens
Your public address comes from a pool at a regional gateway, and the pool can change. T-Mobile’s own published data shows the cities involved.
On this page
T-Mobile US publishes an RFC 8805 geofeed linked from its ARIN registration. It maps blocks of addresses to gateway cities such as Los Angeles, Dallas and New York. When your connection is handed a different public address, sites can place you in a different city. Your device location and account settings beat any IP lookup; for a wrong country, contact T-Mobile and the site.
T-Mobile tells the databases where its addresses are
The registry record for T-Mobile’s block 172.32.0.0 to 172.63.255.255 at ARIN carries the line Geofeed https://raw.githubusercontent.com/tmobile/tmus-geofeed/main/tmus-geo-ip.txt.[1] That is the discovery method RFC 9632 describes: a geofeed reference in the registry record, served over HTTPS.[4]
The file itself is an RFC 8805 geofeed.[3] On our check date it began with the header “T-Mobile US Geofeed, lastupdated 2026-06-29” and had 3,039 entries naming 78 cities, plus 37 entries that give only the country.[2] Lines look like this:
172.56.64.0/21,US,US-GA,Atlanta,
172.56.192.0/21,US,US-MA,Boston,
172.56.160.0/21,US,US-NY,New York,The most common cities in the file were Los Angeles, Dallas, New York, Seattle and Chicago.
Why your city changes
A block such as 172.56.64.0/21 is used at one gateway city, and many customers share it. When your connection is handed an address from another block (after a restart, a network change or simply over time), any database that follows the feed moves you to that block’s city. Nothing about your home changed; your public address did.
Mobile networks also commonly put many customers behind shared public addresses. The address range reserved for that, between customers and the provider’s NAT, is the RFC 6598 shared space, 100.64.0.0/10.[5]
| You see | Likely reason | What helps |
|---|---|---|
| A different big city than last week | A new public address from another gateway block | Nothing breaks; set your location in the site where it matters |
| The right city on your phone’s map, a wrong one on websites | Maps use device location, websites use the IP | Allow location for the site |
| A wrong country | A database not following the feed, or an error in it | Contact T-Mobile with the address and date, then the site |
Check your current city
See which gateway city each source gives your connection today.
Open the Truth CheckWhat to ask support
Have your current public address, the date and time, and what the site showed. Ask whether the address is listed correctly in their geofeed and whether it is shared through carrier-grade NAT. If a site keeps refusing you, ask the site to use your account location or device location instead of the IP; that is the only fix that does not depend on which gateway you land on.
Sources
- RDAP record NET-172-32-0-0-1 (T-Mobile USA, Inc.) · ARINChecked 5 Oct 2026
- T-Mobile US geofeed (RFC 8805, “lastupdated 2026-06-29”) · T-Mobile US on GitHubChecked 5 Oct 2026
- RFC 8805: A Format for Self-Published IP Geolocation Feeds (Aug 2020) · IETF / RFC EditorChecked 5 Oct 2026
- RFC 9632: Finding and Using Geofeed Data (Aug 2024) · IETF / RFC EditorChecked 5 Oct 2026
- RFC 6598: IANA-Reserved IPv4 Prefix for Shared Address Space (Apr 2012) · IETF / RFC EditorChecked 5 Oct 2026