Dear Alexey,

28 Jun 21 23:45, you wrote to me:

 VS>> What if I had two IPv6-capable ISPs for my home, and a /64 or a
 VS>> /56 from each of them? Is it possible to setup a backup link this
 VS>> way?

 AV> Yes.

 VS>> I know that my home router can advertise multiple global IPv6
 VS>> prefixes into the LAN, but how will LAN hosts failover to the
 VS>> backup gateway if the primary ISP fails? They will have IPv6
 VS>> addresses from both blocks, which should they choose for their
 VS>> outgoing src address?

 AV> This is the preferred mode of operation, but it has (only) two
 AV> disadvantages: 1. All hosts in the LAN must be able to do the
 AV> switching|balancing on thy own (that means, run Linux; the BSD-style
 AV> networking stack, like the one used in Windoze, has very limited
 AV> functionality). 2. This may require some manual configuration on every
 AV> of them. Not really a problem, but may be boring.

This is not feasible because most of those LAN hosts are smartphones, smart TVs, vacuum cleaners, cameras and other IoT devices.

 VS>> With two IPv4 ISPs and NAT, the setup is rather trivial, outgoing
 VS>> connections will work via either of the ISPs because the hosts
 VS>> needn't be aware of the failure, and their src private IP is
 VS>> always the same. Can anyone enlighten me?

 AV> This is second option, but you'd lose the main advantage of IPv6: the
 AV> use of publicly routed addresses.

Indeed. I don't like the idea of using NAT in IPv6 even if I could. So what's the solution?

Victor Sudakov, VAS4-RIPE, VAS47-RIPN
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