Multiple DHCPv6 Clients on Same Interface

RouterOS General
1

I know it’s not Mikrotik’s fault, but the AT&T Arris BGW210-700 modem I am having to work with here is pretty weird how it does things. This post is somewhat similar to the post here.

Using the DHCPv6 Client on Mikrotik, I can get a /64 from this modem. Doesn’t matter what I put in the prefix hint, that is always what it gives. If I plug another Routerboard device into the modem and use DHCPv6 Client on that, I can get it to hand out another new prefix to the new router. From reading online, it will apparently hand out up to 8 prefixes like this (the modem supposedly gets a /60 but takes the lower /61 for itself).

So the question is, given what I have described above, how would you go about requesting multiple /64 addresses for a Mikrotik router? In theory, what I need is to put 8 DHCPv6 Clients on one interface to get 8 /64 prefixes. Obviously I am only allowed one DHCPv6 Client per interface on RouterOS. Is there some kind of virtual interface you think I could use here to get around that limitation? Should I try connecting multiple ethernet cables between the modem and router and just run one DHCPv6 Client on each of them?

I am working with a Hyper-V CHR VM at the moment, but I have an RB3011 at another location, and will potentially move to a CCR2004 router in the near future for this location, so a solution that is kinda universal would be appreciated (i.e. on a VM I could create additional virtual interfaces, but on physical hardware not so much).

2

I just tried using Sob’s solution where he used VRRP to put multiple DHCP clients on one interface. Unfortunately it doesn’t work because the DUID of the DHCPv6 client is identical to for every DHCPv6 Client. Again, not blaming Mikrotik here. That is how the DUID is supposed to work, but it’s still disappointing we can’t edit the DUID (it’s even more disappointing that a behemoth like AT&T doesn’t understand how to implement IPv6 though). Even if I used multiple physical interfaces to connect to the modem, the DUID would be the same across all of them, meaning the additional DHCPv6 Clients would not work.

I guess I will have to wait until either Mikrotik allows modifying the DUID on the DHCPv6 Client, or Arris updates their modem to respect prefix hints.