in my lab i am in need of an IPv6 router that will play the role of the ISP. That ISP router will not be connected to the outside world and it is only to simulate a few things. That ISP router will connect to a switch that 2 other routers will get connected as clients. So my idea is to have a debian PC with one ethernet card to offer through DHCP a block of IPv6. My concern is how can i push that block in each connection. ISP router--> switch-->client router A & client router B. Each of the client routers will be a debian PC with 2 ethernet cards. eth0 that will connect to the ISP switch and the eth1 that connects to their LAN switch and advertise the pushed IPv6 block. Some help please?
Your ISP router will need to offer a default route using router advertisements and addresses using DHCPv6 Prefix Delegation. For every delegated prefix it will have to update its routes as well.
The client routers will need to take the delegated prefix and use it to configure its interfaces. Those interfaces will in turn need to send router advertisements so that clients can connect.