"Steven M. Bellovin" <smb%cs.columbia.edu@localhost> writes:
21:26:30.393860 IP6 (hlim 255, next-header: ICMPv6 (58), length:
56) fe80::211:xxxx:xxxx:xxxx > ff02::1: [icmp6 sum ok] ICMP6,
router advertisement, length 56
hop limit 64, Flags [none], pref medium, router lifetime
1800s, reachable time 0s, retrans time 0s
source link-address option (1), length 8 (1):
00:yy:yy:yy:yy:yy
0x0000: 00yy yyyy yyyy
prefix info option (3), length 32 (4): 2001:zzz:z:zzz::/
56, Flags [onlink, auto], valid time 2592000s, pref. time 604800s
0x0000: 38c0 0027 8d00 0009 3a80 0000 0000 2001
0x0010: zzzz zzzz zzzz 0000 0000 0000 0000
Both speak v6 successfully with manually configured v6 addresses on
that
net.
/56?? It's fine for you to get a /56 from your provider (static or
BGP), but the convention is that prefixes for a link are /64. So
that's
probably running afoul of a sanity check later, at least for stateless
autoconfiguration.
If you have a /56, then that leaves you 8 bits for subnets. Assuming
your tunnel uses some other addresses from your provider, I would
assign
subnet 1 to your lan, and then use more as needed.
Hence 2001:pppp:pppp:ppp1::/64 as your prefix.