IPv6 autoconfiguration

RouterOS General
1

Hi,
I’ve got an RB2011 since a while in the following scenario:

DSL-Router ↔ RB2011 ↔ Clients

The DSL Router uses an IPv6 tunnel provider and also supports DHCPv6-PD which is enabled.
Now a few months ago I set everything up including IPv6 which worked all the time until now. I found that my clients do not get any (global) IPv6 addresses assigned anymore. Part of the problem is, that I forgot what I did exactly in the beginning to make it work.

What I want is the RB to provide radvd/ND packets so the clients can get a valid IPv6 prefix and configure local addresses.
What is no problem is that I get a prefix assigned from the DSL-Router:

[admin@MikroTik] > ipv6 pool print
Flags: D - dynamic 
 #   NAME  PREFIX                                      PRE EXPIRES-AFTER       
 0 D ipv6  2001:xxxx:f85a:fc::/62                       62 1h49m47s

But this pool is not advertized to the clients which I would have expected.
Now what I did as a workaround is to add a local address to the RB:

[admin@MikroTik] > ipv6 addr print
Flags: X - disabled, I - invalid, D - dynamic, G - global, L - link-local 
 #    ADDRESS                                     FROM-... INTERFACE        ADV
 0 DL fe80::4e5e:cff:fe06:ea46/64                          bridge-local     no 
 1 DL fe80::4e5e:cff:fe06:ea45/64                          ether1-DSL       no 
 2 DL fe80::4e5e:cff:fe06:ea48/64                          vlan-freifunk    no 
 3  G 2001:xxxx:f85a:fc::1/64                              bridge-local     yes

After doing so all seems fine so far but it will stop working at least at the point where the DHCPv6-PD prefix above changes for some reason.
I guess there must be a “right way” to do it but so far I haven’t found it.

Any pointers?


Thanks,
Wolfgang

2

Somehow I seem to ask the wrong questions in this forum? Nobody any hint? Also asking because I now want ROS to provide a different IPv6 subnet on another interface which I tried somehow but it didn’t accept my setting. I still think something in my basic configuration is not exactly as expected.

3

Do not add manually ip address, use from-pool instead

/ipv6 address add address=::1/64 from-pool=ipv6
4

What about this issue?
http://forum.mikrotik.com/t/fixed-in-6-34-ipv6-address-from-pool-stays-invalid/85590/1

I would love to have this fixed.

5

I’m wondering if I have seen this as well.

In any case I’ve now defined my address from the pool. That’s hopefully fine for the beginning.

But I still have a misunderstanding. So in my example I get from DHCPv6-PD an assignment with a /62 network. How can I create multiple /64 pools out of this which I would expect to serve different networks connected to different interfaces? Again manually sounds wrong if the assignment itself is dynamic but I do not find anything in the configuration.

6

You create the pool with a name (e.g. mypool) and a prefix length = 64.
This prefix length specifies what size slices you’re going to chop up any prefixes you receive.

When dhcp client receives a prefix from dhcp-pd, then it sets the Prefix accordingly.

So if dhcp-pd gives 2001:db8:1234:5678::/62 then this means that you have the following /64 prefixes to play with:
2001:db8:1234:5678::/64
2001:db8:1234:5679::/64
2001:db8:1234:567a::/64
2001:db8:1234:567b::/64

If you set an interface address using from-pool = mypool , then the system will choose an available one of those 4 /64 prefixes and use it on the interface.

7

Thanks a lot. Now I got it and it’s working finally.