c/networking · by walden@wetshav.ing · 186d

Update on Frontier IPv6

I made this post 3 months ago: https://sh.itjust.works/post/50242033

@stevetech@aussie.zone was super helpful in checking that my Mikrotik configuration was set up correctly. There's a mess of IPv6 information out there for Mikrotik and it's confusing for a mid-nerd like myself.

Anyway, I checked the other day and boom, I had a prefix assigned by my ISP (Frontier).

Unfortunately Frontier has decided to give out /64 prefixes. The downside to that is you can't use SLAAC inside your LAN to do subnetting (guest networks, VLANs, etc).

So my next step is to learn about DHCPv6 to manage things inside my LAN.

There are comments on other forums that are hopeful that since Verizon bought Frontier, they'll eventually switch to handing out /56 prefixes.

12 points · 3 comments · view on lemmy.world

3 Comments

SteveTech@aussie.zone · 2 pts · 186d (2 replies)

Wow, thanks for the update!

Edit: You can possibly look into NPT if you want to use SLAAC on your LAN, it's like NAT but for your prefix, so the connection is still somewhat end to end.

Although one thing to note, fd00::/8 is allocated to be used as a private address, however most browsers will prioritise IPv4 over these ULA addresses. You can pick your own prefix from the unallocated addresses, which is kinda sketchy but then browsers trust it.

walden@wetshav.ing · 1 pts · 11d (1 reply)

It has been a while, but I've learned a lot about IPv6 since 5 months ago.

To recap - you helped me get IPv6 set up on my Mikrotik router, but Frontier only gives me a /64. In this comment you recommended looking into NPT to help subnet my LAN.

I think this is basically what I'm doing, but I'll do some more reading about it. Right now I'm using IPv6 Firewall -> NAT -> some masquerade rules for the ULA addresses I have set up.

Like you said, they don't really reach the outside world as IPv6, since IPv4 takes priority over them.

So just to clarify, you're saying if I assign a random, unallocated GUA in the same fashion, and then NAT it to the prefix from my ISP, that could get around the browser limitation?

SteveTech@aussie.zone · 1 pts · 11d

Hi again!

Right now I’m using IPv6 Firewall -> NAT -> some masquerade rules for the ULA addresses I have set up.

So, masquerade is not NPT, as NPT will translate the prefix but leave the host portion the same, whereas masquerade will translate everything to the Router's IP. Although I don't remember if MikroTik will let you NPT with multiple subnets, so it might not work, but you could probably steal some bits from the host portion.

So just to clarify, you’re saying if I assign a random, unallocated GUA in the same fashion, and then NAT it to the prefix from my ISP, that could get around the browser limitation?

Yep, and I'd pick something on the higher end (such as 3ffe::/16), not just completely randomly.

I believe I got this from 'Paul's blog':

ULA + NPTv6 is non-viable for external connectivity. Recommended listening: IPv6 Buzz episode 90 where they conclude that there aren't that many good use cases for ULA. One of the options that they (legitimately!) discussed was squatting on some unused portion of the IANA IPv6 allocation, e.g. the 3000::/4 space. I would probably do that ahead of using ULA, but would never recommend it to anyone.