the wan side gives you the prefix. usually a /64
Can I confirm we're talking about the same thing, I must admit that when talking/thinking IPv6 I sometime revert to thinking in IPv4 terms.
For comparison on my connection I get a WAN address for the WAN interface. My DSL is PPPoA so I believe that's negotiated by PPP (IPCP?) rather than DHCP. (I'll need to remember to look at a PPPoE customer to see if that uses DHCP, but my guess would still be IPCP). The WAN address prefix is different from the /64 prefix assigned to my line for me to use internally.
I'll need to have a check - I'd assumed that the customer/internal prefix wasn't pushed out as I'd seen no mention of this possibility either in the router documentation or A&A, however I might have missed it, or maybe the function doesn't work on PPPoA or on my kit.
WAN 2001:8b0:1111:1111:0:ffff:xxxx:a27e
Internal 2001:8b0:fff3:yyyy::/64By the way, for those of us who remember Novell addressing, we now have the option to make addresses contain silly words once more.