I have received an IPv6 network from my provider, say it's 2001:db8:1::/48. I did not get delegated prefix from them.
I would like to use the IPv6 addresses on different networks behind a firewall (Sophos UTM)
So I assign the address 2001:db8:1::1 to the Internet port of the firewall with the prefix length being 48 as communicated by the provider. The provider's address was said to be 2001:db8:1::2. This connection seems to work fine.
Now I want to use several networks behind this firewall. Which ones could that be? I do not want to use things like NAT, as there are many addresses available and NAT should not be needed anymore with IPv6...
I decided to use the subnet 2001:db8:1:1::/64 (S1) and 2001:db8:1:2::/64 (S2) on two interfaces of the firewall. But now, the same IPv6 addresses are used on two interfaces and I am not sure if this it's correct. Also, it does not work at all.
I think I also understand, why:
Let's say a client in one subnet wants to connect to a client on the other subnet:
2001:db8:1:1:100 wants to connect to 2001:db8:1:2:200.
But on which network should the host 2001:db8:1:2:200 be? The IPv6 addresses both belongs to the network on the Internet interface (2001:db8:1::/48) and to the network S2 (2001:db8:1:2::/64) I fully understand that the firewall does not know where to route the packets...
But how to solve this? What would be the solution to this problem? Do I really net NAT? How to use all the many IPv6 addresses the provider allowed me to use? Maybe I didn't fully get some principles for IPv6, but all the other networks where the provider delegated a subnet to me, are working great.
So, can anyone explain to me how to configure my network to make my setup work?