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I'm probably asking this the wrong way, but here it is; I have a /48 block with static addresses for every device on the network. Everything is routed, no NAT, no tricks.

My question is: on a mobile device like a cellphone or tablet, what if I wanted to keep my internal--which is actually a global--address outside the bounds of my upstream router?

Without tunneling, is there a way to dynamically recreate routes after each cell/wirelessAP attached to a network to which my device comes in contact?

I'd love to check for myself but both of the carriers I have service with lack IPv6 support, so I do tunnel in.

  • Not likely. It'd require BGP advertising your own AS (/48 is the minimum size). I don't think any ISP allows BGP on mobile. – Zac67 Feb 10 at 10:58
  • @Zac67, we have some mobile (4G) connections for backup at some sites, and the carriers allow us to use BGP. There are some strange restrictions, like requiring a /64 IPv6 network for every point-to-point link between our "mobile" routers and the ISP routers. Apparently, that requirement is because of some standard that the mobile providers have created. They originally told us that we should use /126 for the point-to-point links, but this standard popped up, and we had to change that. – Ron Maupin Feb 10 at 15:23
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The ISPs will not route any IPv6 prefix longer than /48, and certainly not a /128 address for a single device, but there is Mobile IPv6 that automatically builds a tunnel back to the "home" network agent. You will need a router on your network that supports Mobile IPv6 to be the Home Agent for any mobile devices.

There are sources that explain Mobile IP at a high level, including the Wikipedia Mobile IP article. If you search for rfc mobile ipv6, you will see many RFCs for various aspects of IPv6 mobility:

  • Mobile IPv6 is definitely the way to go, but operating system support is very limited right now, surprisingly. There's some stuff you can hack together on Linux. Supposedly mobile IPv6 has existed in Windows forever, but good luck finding anything about actually setting it up. AFAIK Android and iOS have nothing either. This is unfortunate as it solves a lot of problems, or would if we had usable host implementations. – Michael Hampton Feb 10 at 16:57

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