Hello,
How to perevnt IPV6 Leak while using an L2TP + IPsec Client to VPNProvider?
Or even better how to change my current setup so i can use the IPV6 Nat from my VPNProvider?
Thanks for your help!
since we don’t know your current setup, it’s hard to tell 
i never used NAT on IPv6 - i guess the point of using IPv6 is to be transparent. whatever your provider uses to achieve this functionality must work, as long you route all traffic towards the L2TP tunnel. as far as i guess, L2TP still runs only over IPv4, just make sure your IPv6 client will install a default route (add-default=yes) and its administrative distance is lower than your current (default-route-distance=xxx)
Feature Request L2tp Client with ipv6 IP trough ipv4 Tunnel.
Leaking is caused by tunnelbroker… These broker leaks IP, firewall and local information behind nat to non-eu servers.
Block UDP 3354 and DNS Blacklist these.
Thanks for your help