IPV6 howto on at&t Arris Modems multiple ipv6 addresses on multiple interfaces

[symgryph]

I found a very nice HOWTO (for the opposing firewall, name shall not be mentioned). Which details how to get the ipv6 working on multiple interfaces. I did find this article here:

https://forum.opnsense.org/index.php?topic=17720.0

Alas, it doesn't really detail how to get everything working. I had it working great on the 'other' firewall (it rhymes with rents, and has a gate in a certain name), however I really prefer opnsense.

I have created a GitHub page, which references the 'original' document which solved this issue. I am linking here so you don't have to manually figure everything out.

https://github.com/symgryph/multiple-ipv6-att-opnsense

[bogen85]

I tried this with AT&T and Spectrum. (Adjusted config files for each appropriately for each setup of course).

So far seems to work on both, but have not fully tested yet.

At least existing interfaces/subnets still work (with new prefix IDs if applicable) with IPv6.

Before using this custom config file I was not able to specify a prefix other than 0 for a LAN interface. This limited tracking of a WAN interface for IPv6 address allocation to one LAN interface only.

With this custom config multiple LAN interfaces can track the same WAN interface for IPv6 (by specifying a different prefix per LAN interface)

[symgryph]

Would you mind posting a PR for your config? I would love to post...... or just post here and I will update.

[bogen85]

Would you mind posting a PR for your config? I would love to post...... or just post here and I will update.

Well, I followed the same pattern as your example, that did not change.
Only thing I had to change was the interface names in each custom config file.

This was done on two separate routers (one for AT&T, one for Spectrum) so no needed change from the example you provided.

I will be combining both into the same router (have both providers so if one goes out, hopefully the other won't be out at the same time) so that is where something may have to change in the custom config. Of course the IPv6 tracking of the down WAN interface won't work, so I'll need to have config files I switch between when one goes out. And I've not worked out which subnet will use what provider when both are up, etc.

Prefixes can be skipped (I tried this), so even if I have some local subnet interfaces on one provider, and some on the other, I should be able to have a unique prefix per local subnet interface, regardless of which WAN interface it is tracking.

I initially had both in the same router, and it showed promise, but the IPv6 address tracking across multiple subnets not working is what made me switch to a two router interim solution.

Eventually I'm going to have at least 4 physical local subnet interfaces/networks using two upstream WANs. Ideally IPv6 tracking for multiple interfaces and failover for the WANs would be something the WebUI could handle. But for now the failover will likely be a manual process.