Cant get IPv6 using DHCPv6 Client

fellipeh · Mon Aug 01, 2022 4:53 pm

Hey, y'all!

I have an hEX (mmips) with RouterOS 7.4, and my ISP uses a Huawei router, here are some facts from my network:
- When I create a DHCPv6, the status is always "Searching..." it doesn't change..
- My ISP delivers an IPv6 prefix through PPPoE - I know my ISP delivers an IPv6, because I have a HUAWEI WiFi WS5200, and when I connect it, I can get the IPv6 address for all my devices, using SLAAC.
- I tried to go back the RouterOS to v.6x, and doesn't work, still "Searching"
- I tried to create my DHCPv6 using my pppoe interface, the eth interface, and the bridge interface.. same issue...

- Here is my ND:

Flags: X - disabled, I - invalid; * - default 
 0  * interface=all ra-interval=3m20s-10m ra-delay=3s mtu=1500 reachable-time=5m retransmit-interval=unspecified 
      ra-lifetime=30m ra-preference=medium hop-limit=unspecified advertise-mac-address=yes advertise-dns=yes 
      managed-address-configuration=yes other-configuration=yes dns=""

- Here are my IPv6 settings:

                  
                  disable-ipv6: no
                       forward: yes
              accept-redirects: yes-if-forwarding-disabled
  accept-router-advertisements: yes-if-forwarding-disabled
          max-neighbor-entries: 8192

I don't know how to proceed from now.. any help will be very, very welcome!!

Cheers!

tdw · Mon Aug 01, 2022 5:34 pm

You can only acquire an address with the DHCPv6 client if the provider supports it.

The most common mechanism is to use received router advertisments (RA) which unfortunately are not displayed by RouterOS, as discussed in other forum posts, and was completely broken in earler releases of RouterOS v7. The default IPv6 settings include forward=yes and accept-router-advertisements=yes-if-forwarding-disabled, so as you are forwarding you need to set accept-router-advertisements=yes.

You can then use the DHCPv6 client to acquire a prefix, and assign IP addresses from that prefix to your LAN(s).

ND is for advertising to your LAN devices, the managed-address-configuration=yes is incorrect as the Mikrotik DHCPv6 server does not support address assignment, the other-configuration=yes setting is only required if you intend to provide non-address information from the DHCPv6 server.

sindy · Mon Aug 01, 2022 6:11 pm

Unless Huawei is doing something very special, it should be a configuration issue.

In IPv6, the roles and capabilities of a "router" and "host" are separated much more strictly than in IPv4, and also DHCP works slightly differently.

Your router must request a prefix (subnet) from the ISP router, and assign that prefix to a local named pool. Your router will not get a global IPv6 address on the WAN (PPPoE) interface automatically, and you even don't need any global address on WAN. It is enough that you assign a global address from the pool to the LAN interface, so that your clients could get their global addresses via SLAAC. The global adress assignment for LAN contains the lower part of the address, and the prefix is taken from the pool. So maybe one part of this chain is missing, and Mikrotik doesn't send the DHCPv6 requests due to that?

Another thing is that unlike DHCP for IPv4, DHCPv6 is not hooked closer to the interface than the firewall. And since the client sends the request to a multicast address, but gets the response from a unicast one, the "accept established,related" rule is not sufficient to accept the response. So chain input of your /ipv6/firewall/filter may block the server's responses.

afardana · Wed Jan 11, 2023 3:20 pm

Another thing is that unlike DHCP for IPv4, DHCPv6 is not hooked closer to the interface than the firewall. And since the client sends the request to a multicast address, but gets the response from a unicast one, the "accept established,related" rule is not sufficient to accept the response. So chain input of your /ipv6/firewall/filter may block the server's responses.

For my case, this is exactly what is needed to allow DHCPv6 PD response from upstream.
The entry would be like this:

/ipv6/firewall/filter
;;; Accept DHCPv6-Client prefix delegation.
      chain=input action=accept protocol=udp src-address=fe80::/16 dst-port=546

csurata · Tue Aug 01, 2023 3:19 am

Hey, y'all!

I have an hEX (mmips) with RouterOS 7.4, and my ISP uses a Huawei router, here are some facts from my network:
- When I create a DHCPv6, the status is always "Searching..." it doesn't change..
- My ISP delivers an IPv6 prefix through PPPoE - I know my ISP delivers an IPv6, because I have a HUAWEI WiFi WS5200, and when I connect it, I can get the IPv6 address for all my devices, using SLAAC.
- I tried to go back the RouterOS to v.6x, and doesn't work, still "Searching"
- I tried to create my DHCPv6 using my pppoe interface, the eth interface, and the bridge interface.. same issue...

- Here is my ND:
Code: Select all
Flags: X - disabled, I - invalid; * - default 
 0  * interface=all ra-interval=3m20s-10m ra-delay=3s mtu=1500 reachable-time=5m retransmit-interval=unspecified 
      ra-lifetime=30m ra-preference=medium hop-limit=unspecified advertise-mac-address=yes advertise-dns=yes 
      managed-address-configuration=yes other-configuration=yes dns="" 
- Here are my IPv6 settings:
Code: Select all
                  
                  disable-ipv6: no
                       forward: yes
              accept-redirects: yes-if-forwarding-disabled
  accept-router-advertisements: yes-if-forwarding-disabled
          max-neighbor-entries: 8192
I don't know how to proceed from now.. any help will be very, very welcome!!

Cheers!

Hello friend the problem was solved with version 7?

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