REPLY: 2:5005/49 60db3242   
   MSGID: 2:5020/545 60dbd819   
   CHRS: CP866 2   
   TZUTC: 0300   
   Good ${greeting_time}, Victor!   
      
   29 Jun 2021 21:43:24, you wrote to me:   
      
    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   
    AV>> BSD-style networking stack, like the one used in Windoze, has   
    AV>> very limited functionality). 2. This may require some manual   
    AV>> configuration on every of them. Not really a problem, but may   
    AV>> be boring.   
    VS> This is not feasible because most of those LAN hosts are smartphones,   
    VS> smart TVs, vacuum cleaners, cameras and other IoT devices.   
      
   Most of these devices have Linux kernel, but crippled userspace.   
      
    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:   
    AV>> the use of publicly routed addresses.   
    VS> Indeed. I don't like the idea of using NAT in IPv6 even if I could.   
    VS> So what's the solution?   
      
   For dumb devices, especially portable, I'd suggest using NPT. Fully functional   
   computers may be connected to some other VLANs (two at once in your case) and   
   configured to use real addresses.   
      
      
   --   
   Alexey V. Vissarionov aka Gremlin from Kremlin   
   gremlin.ru!gremlin; +vii-cmiii-ccxxix-lxxix-xlii   
      
   ... GPG: 8832FE9FA791F7968AC96E4E909DAC45EF3B1FA8 @ hkp://keys.gnupg.net   
   --- /bin/vi   
    * Origin: ::1 (2:5020/545)   
   SEEN-BY: 1/123 30/0 80/1 90/1 105/81 120/340 123/131 124/5016 154/10   
   SEEN-BY: 203/0 221/0 1 6 226/30 227/702 229/424 426 550 700 1016 240/1120   
   SEEN-BY: 240/5832 249/206 317 400 261/38 280/464 5003 5006 5555 282/464   
   SEEN-BY: 282/1038 292/854 8125 301/0 1 101 113 812 310/31 317/3 322/757   
   SEEN-BY: 342/200 423/120 460/58 633/280 712/848 770/1 920/1 2452/250   
   SEEN-BY: 5020/545 736 1042 5058/104   
   PATH: 5020/545 280/464 301/1 229/426