Dear Richard,   
      
   26 Jul 18 12:26, you wrote to me:   
      
    VS>> My phone and tablet sometimes use IPv6, sometimes they won't, and   
    VS>> I find no obvious way to monitor and influence this process.   
      
    RM> My mobile connection is IPv4 only.   
      
   Mine too.   
      
    RM> But when I am connected with WiFi at home it will consistently have   
    RM> dual stack.   
      
   My phone can also be dual stack (it shows both the IPv4 and the IPv6 addresses   
   in the network properties, and the IPv6 address is the correct public address   
   from my home WiFi network), but http://test-ipv6.com/ in the Chrome browser   
   shows that IPv6 is not available. Sometimes it shows that IPv6 is available   
   but is not preferred.   
      
   Any ideas would be appreciated.   
      
   Victor Sudakov, VAS4-RIPE, VAS47-RIPN   
   --- GoldED+/BSD 1.1.5-b20160322-b20160322   
    * Origin: Ulthar (2:5005/49)