From: as@sci.fi   
      
   I've been recently playing with IPv6 but I have a vexing problem with my   
   little Ubuntu box. Systemd-networkd (from systemd 245.4) is supposed to   
   understand a directive  like this:   
      
   IPv6Token=prefixstable:my_prefix   
      
   where my_prefix is exactly what my router sends in its RA, 64 bits,   
   ending in a double colon (::), verified by tcpdump. And what I wish to   
   get out of this is an IPv6 address generated as described in RFC7217,   
   i.e. a stable address where the lower 64 bits are not based on my MAC   
   address.   
      
   Unfortunately systemd-networkd does not seem to agree. It accepts the   
   directive without comment but I still get the EUI-64 address. Even if I   
   set log level to debug there's nothing in the log about this. I've tried   
   other forms in my_prefix but then networkd eagerly tells me it's wrong   
   but not what would be correct and actually *work*.   
      
   I can work around this in a bunch of ways so not looking for that,   
   but getting this to work would be easiest.   
      
   I looked but I haven't found any bug reports about this so I have a   
   feeling it should work. Any ideas?   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)