Hello Tony,   
      
   On Tuesday January 30 2018 12:49, you wrote to me:   
      
    MvV>> So, let me get this straight. You have a native IPv6 connection   
    MvV>> with your ISP and your IPv4 connection is via a tunnel. The   
    MvV>> reverse of what I have been doing with my 6in4 he.net tunnel   
    MvV>> that I used before I got native IPv6 from my ISP. Right?   
      
    TL> Pretty close.  The IPv4 tunnel is actually carried on IPv4 via the   
    TL> router's NAT.   
      
   OK. You mentiond: "I could become temporarily IPv6 only (incoming and   
   outgoing)," and that put me on the wrong foot.   
      
    TL>   I got the tunnel, because I wanted multiple public IPv4 addresses.   
      
   That part I understood.   
      
    MvV>> So when that tunnel folds, you no longer have IPv4 incoming on   
    MvV>> the advertised addresses. Right?   
      
    TL>> Same for incoming only, because I would lost all IPv6   
    TL>> connectivity in this situation.   
      
    MvV>> s/IPv6/IPv4/ ?   
      
    TL> Yep, oops typo lol.   
      
   OK.   
      
    MvV>> But... your basic connection is not really IPv6 only is it? If   
    MvV>> it is you would be rather unique. AFAIK, no end user has an IPv6   
    MvV>> only connection yet. It is either Dual Satck or DS-Lite. In   
    MvV>> either case you still have outgoing IPv4 capabiity. No?   
      
    TL> It's dual stack, it's just because of how the actual IPs for the BBSs   
    TL> are obtained (as additional IPs) there is this quirk.   
      
   BBSs are incoming only. So if the tunnel is off-line, your BBS users could   
   only use IPv6 to connect to your BBS.   
      
   Your mailers however are both client and server. They could still use the IPv4   
   address from the dual stack connection for outgoing connections. (if so   
   confugured).   
      
   BTW...   
      
   @MSGID: 239.fido-ipv6@3:633/410 1ed58d3d   
      
   My software (Fmail, Golded) does not like your not FTS-0009 complient MSGID.   
   It breaks the reply linking.. :(   
      
      
   Cheers, Michiel   
      
   --- GoldED+/W32-MSVC 1.1.5-b20170303   
    * Origin: he.net certified sage (2:280/5555)