In my opinion, after selecting the “Add default route” option, the pppoe-client should not add a default route entry with the pppoe-out interface as the gateway in the IPv6 routing table. Because adding an IPv6-DHCP-client and selecting the ‘Add default route’ option will add an IPv6 default route, the two functions overlap. What do you think?
This issue still exists in the latest 7.19rc2 version.
That’s why you should not turn on Add Default Route for DHCPv6 Clients on PPPoE client connections. You are on this forum long enough, you should also have known that people here recommend turning off Add Default Route on DHCPv6 Clients for other types of non-PPPoE interfaces too, and only enable it in some specific cases where RA is not working at all.
DHCPv6 has no concept of “default gateway” or “default route”, it’s not defined in the standard at all! The check box that you see on the DHCPv6 Client instance is a specific hack from MikroTik, where the router just uses the IPv6 address of the remote DHCPv6 server as gateway IP address. Sometime this work, sometime this is completely wrong, especially when relays are involved. Let me repeat once more: the default route/gateway is not an information that the DHCPv6 server can provide, unlike DHCPv4.
So, in case of PPPoE client, turning on “Add Default Route” on pppoe-out is the correct way and the recommended way, and turning on “Add Default Route” on the DHCPv6 client is a hack that should not be done.
Because adding an IPv6-DHCP-client and selecting the ‘Add default route’ option will add an IPv6 default route
This is wrong in most cases.
Unlike IPv4 the IPv6 DHCP protocol has no concept of a default gateway, the Mikrotik DHCPv6 client option to add a default route is a bodge - it uses the address of the DHCPv6 which replies as the gateway address. For IPoE setups this often works, but if the ISP gateway and DHCPv6 server have different addresses you end up with no connectivity.
In general:
Accept router advertisments should be enabled, this allows the gateway and a WAN SLAAC address to be determined automatically on IPoE connections. With PPPoE connections this may not be necessary as the gateway and WAN address should be provided during the PPP IP6CP negotiation.
Use DHCPv6 to obtain a delegated prefix only. Some ISPs require the WAN address to also be obtained with DHCPv6, rather than SLAAC, on IPoE connections.
… and in such case configure DHCPv6 client to require both prefix and address in a single handshake (set request=prefix,address on DHCPv6 client configuration).
Thank you for your guidance. I come from a non-native English speaking region. Sometimes it is difficult to accurately search for the required consultation on the forum, regardless of the length of registration time.
Thank you for your guidance. I come from a non-native English speaking region. Sometimes it is difficult to accurately search for the required consultation on the forum, regardless of the length of registration time.
Thank you for your guidance. I come from a non-native English speaking region. Sometimes it is difficult to accurately search for the required consultation on the forum, regardless of the length of registration time.