T-Mobile's journey to IPv6

What Hacker News said

Cites throw0101a · 2022-06 · on “Is IPv6 faster than IPv4?”

> Anyone running v6 only and bridging to v4 on the edge? If you are on T-Mobile USA you are IPv6-only on your mobile device: * [this video] * [LINK] Lots of folks are probably IPv6-only without realizing it.

Cites throw0101c · 2022-12 · on “Tell HN: IPv6-only still pretty much unusable”

> All mobile clients are behind CG-NAT. Demonstrably false. T-Mobile US mobile clients are IPv6-only and connect via IPv6 to IPv6 sites: * [this video] * [LINK] NAT is only used to connect to IPv4-only hosts via DNS64 (with or without 464XLAT). As of 2022Q2, T-Mobile US has 110 million customers: * [LINK] One-third of the US population is connecting via IPv6-only on a day-to-day, hour-to-hour basis every time their smartphone reaches out over the radio.

Cites throw0101b · 2023-04 · on “Thinking about our passive exposure to IPv6 issues”

> T-Mobile and Verizon both use CGNAT (but do issue individual ipv6 addresses to end user devices). More specifically, T-Mobile US only assigns IPv6 addresses to devices, and to reach the IPv4 world you have to go through a translation mechanism. Presentations from T-Mobile at NANOG and Rocky Mountain IPv6 Taskforce: * [this video] * [LINK]

Cites throw0101a · 2025-11 · on “ISPs more likely to throttle netizens who connect through CG-NAT: Cloudflare”

> Isn’t essentially the entire US on CG-NAT for IPv4 on mobile data? T-Mobile, for one, has had their handsets IPv6-only for a few years, so if your Android/iOS does a DNS lookup and gets an AAAA record back, it will skip CG-NAT. T-Mobile presenting at NANOG in 2018 on IPv6: * [this video] And Rocky Mountain IPv6 Taskforce in 2017: * [LINK] Further data: > Chances are if you use the Internet on your smartphone, you are connecting via IPv6. According to the Internet Society’s 2018 State of IPv6 Deployment,[1] 80% of smartphones in the US on the major cellular network operators use IPv6 and major mobile networks are driving IPv6 adoption with Verizon Wireless at 84%, Sprint at 70%, T-Mobile USA at

Cites throw0101c · 2025-12 · on “I spent a week without IPv4 (2023)”

> This is the only real reason in my opinion, why IPv6 is doomed to be second-grade citizen for (probably) a few more decades. Except if you're using a mobile phone, in which case many telcos hand out only IPv6 addresses to handsets. 2018 NANOG presentation "T-Mobile's journey to IPv6": * [this video] From 2014, "Case Study: T-Mobile US Goes IPv6-only Using 464XLAT": * [LINK] But who cares about mobile phones, right? They're only second-grade devices.

Cites throw0101c · 2026-04 · on “Why IPv6 is the only way forward”

> IPv6 feels like we just can't admit to ourselves that it has been a failed transition. What would it take to come up with IPv7 which takes in the lessons of IPv6 and produces something better that we can all agree is worth transitioning to over IPv4. Per Google, quite a few countries (including the US) are at >50%: * [LINK] Every handset on T-Mobile US's network gets IPv6 (and they're not the only carrier like that): * [this video] So I'm not quite sure where "failed" enters the equation. And what exactly would be different with IPv7? Anything that needs more address bits would have to update DNS to create new resource record types ("A" is hard-coded to 32-bits) to support the new longer addres

Cites throw0101d · 2026-04 · on “IPv6 Traffic Crosses the 50% Mark for the First Time”

> Outdated beliefs probably. When I talk about v6 support in our b2b saas, PM laughs and says nobody uses that shit. Nobody except the 140M subscribers on T-Mobile US's network: * [this video] But sure, be IPv4-only and add latency by forcing traffic through an extra translation box.

Cites throw0101d · 2026-04 · on “IPv6 Traffic Crosses the 50% Mark for the First Time”

> They've been requiring that iOS apps work on IPv6-only networks for close to 10 years now This was at the behest of mobile network. E.g., T-Mobile US has 140M subscribers, and moved to IPv6-only many years ago: * [this video]