Configuring multiple routable IPv6 subnets with multiple routers

[foo]

A picture can speak a thousand words...

If my ISP provides a /48 IPv6 prefix, can I use three pfSense routers to setup the following topology with everything being routable to/from the internet?

My main sticking point at the moment is what the network configuration between pfSense A---B and A---C should be. Should I allocate a /64 for these links?

Would I need to use a routing protocol (like OSPF) to make everything routable?

Any help and suggestions much appreciated.

[JKnott]

@foo

Yes, routing with IPv6 works just like routing with IPv4. You could pass larger blocks than /64 to another router, to split further. You can repeat that in another stage too. There is one difference though in that with IPv6, the transit network can use link local addresses, instead routeable addresses in IPv4 (Has anyone tried something in 169.254.0.0/16 for a transit network? Should work.).

[foo]

@jknott Thanks for confirming this should work.

I can't get any IPv6 addresses on the LAN interfaces of pfSense B and C.

On router A, I have the LAN A and B interfaces set to tracking. One hase prefix ID 00 and the other 01. I assume this will give have a /64 prefix?

How should I have the router A, LAN A and LAN B interfaces configured to connect to router B and C? Should I use DHCPv6 or RA?

[Derelict]

@foo said in Configuring multiple routable IPv6 subnets with multiple routers:

How should I have the router A, LAN A and LAN B interfaces configured to connect to router B and C? Should I use DHCPv6 or RA?

That depends on what you want to do. You can make static routes to the downstream routers if you want static routing or configure DHCP6 with a prefix delegation if you want dynamic host configuration.

Both will work fine.

Routers B and C will have to be configured, via DHCP6 or SLAAC or both, to provide addressing and routing options to the clients on their downstream networks. Else all clients on those downstream networks will need to be configured statically.

Here is part of the DHCP6 delegation I have that provides the "WAN" interface for a lab segment. I have chosen to operate this segment in "Managed" RA mode (SLAAC "auto" addressing disabled) since the only thing I connect there are downstream routers. They get an address and a /56 PD with which they can do whatever they want.

[JKnott]

@foo said in Configuring multiple routable IPv6 subnets with multiple routers:

How should I have the router A, LAN A and LAN B interfaces configured to connect to router B and C? Should I use DHCPv6 or RA?

Think about how you'd do it in IPv4. You set up routes to say those addresses go there. Same thing with IPv6. This is basic stuff for anyone setting up networks, whether IPv4 or IPv6.