Static IPs, IPv6 and ASUS RT-AC87U router....
We have a (supported) SMC business gateway with several static IPv4 addresses.
On the front end network, connected to the SMC through a switch, are our web server etc., which have both static public IPv4 (75.* network) vaddresses as well as a mixture of static & dynamic IPv4's (10.* frontend network) assigned by DHCP. Also present is an ASUS RT-AC87U router, which has an address on the 10. frontend tnetwork, and which provides addresses to the internal 192.* network via DHCP.
A couple of weeks ago, after an update of the SMC by Comcast, there now is IPv6 working -- at least from systems on the front end network, including the shell of the ASUS router, which can ping -6, access systems on the public IPv6 network.
However, although the ASUS gets (stateful) configuration via DHCPv6, including even a different /64 prefix designation for the internal LAN, which it happily provides via stateful autoconfiguration to the internal network, the internal network systems are unable to access or ping -6 systems on the public network.
The current running theory is that either the SMC or something upstream is not routing the /64 addresses that the internal network is receiving.
The SMC WAN settings from the gatewa are:
|WAN DHCP IPv6 Address||2001:558:600a:2b:3140:8e12:584c:feb2/64|
|WAN DHCP IPv6 DNS (primary)||2001:558:feed::1|
|WAN DHCP IPv6 DNS (secondary)||2001:558:feed::2|
The Front-end LAN gets these settings:
LAN IPv6 Settings
|LAN Gateway IPv6 Address||2601:600:8100:6700::1/64|
|LAN IPv6 DNS (primary)||2001:558:feed::1|
|LAN IPv6 DNS (secondary)||2001:558:feed::2|
|LAN IPv6 Address Lifetime (minutes)||10080|
|LAN IPv6 Prefixs Delegations|
LAN IPv6 ADDRESS
|LAN IPv6 Address:||2601:600:8100:6700::1/64|
The ASUS shows the following:
|IPv6 Connection Type: Native with DHCP-PD|
|WAN IPv6 Address: 2601:600:8100:6700:aa1a:99d7:c8f1:9574|
|WAN IPv6 Gateway: fe80::ba9b:c9ff:fedd:58b6|
|LAN IPv6 Address: 2601:600:8100:67ff::1/64|
|LAN IPv6 Link-Local Address: fe80::3a2c:4aff:feaa:c8d0/64|
|LAN IPv6 Prefix: 2601:600:8100:67ff::/64|
|DNS Address: 2001:558:feed::2, 2001:558:feed::1|
So, it does look like the ASUS is configured to route traffic originating from the internal LAN to the SMC via its link-local address as expected -- thus the conclusion that either the SMC or something upstream is dropping the traffic.