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Comment by unethical_ban | Hacker News Reader

I struggled to get IPv6 running on my home network, then had issues with DNS dual stack once I got it going, so I turned it off.

That said, I think the difficulty of IPv6 is in the UI of the home routers that implement it, and a lack of sane defaults.

The ISP should give every SOHO/residential customer a /60. The router of a simple IPv6 should do prefix delegation. The router should default to SLAAC for local IP addresses, and configuring DNS with Router Advertisements. And residential routers can be set up to have an internal DNS server which populates the ".internal" domain with hostnames from the network.

As a network admin, you have to learn new things like the uses of IPv6 multicast, and ND, the lack of ARP, and some other things. Home users shouldn't have to care about that.

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Sorry, but under no circumstances should an ISP router auto route internal computers from the network. Thats just going to expose so many internal services, most consumers wouldn't even know they were running in the first place.

If we are to have a transition to IPv6, and I am very much in favour of this, then by all means make the addresses be globally routable, but force people to select the ports and addresses to be shared in their router. Otherwise we end up with another mess ala "open wifi".

It doesn't need to, IPv6 has unique local addresses which is are non-globally reachable; I recall those had it's own can of worms depending on deployment but it's an option for private, local addresses.

EDIT: I also understood the GP comment to be getting around the problem of long IPv6 addresses and not actually making every machine globally accessible.

I didn't think I suggested an open firewall.

Just as today people have to adjust NAT as kind of an implicit inbound policy, a proper home IPv6 router defaults to drop for inbound traffic.

That's literally the ISP's and router's job: get packets from A to B.

Now, a home router should probably have a stateful firewall that's on by default, but that's a different matter.

"Auto routing" is fine, as long as there is a firewall.

>The ISP should give every SOHO/residential customer a /60.

The ISP should give every residence 295 quintillion IPv6 addresses? I know there is an abundance of ipv6 addresses but that seems like a lot of waste.

Even assigning a /96 would provide 4.3 billion ipv6 addresses (which is the same number as all ipv4 addresses in existence)

And since available ipv6 space is basically 4.3 Billion^2, assigning an ipv6 /96 would be like assigning a /32 in ipv4 terms of total ipv6 space utilization.

/64 is needed for SLAAC to work and is basically the default.

Anything larger (usually /56, sometimes even /48) gives the customers a chance to segment their LAN.

Like other person said, /64 is the minimum subnet size. And submitting in ipv6 is best done 4 bits at a time. A /60 is overkill for residents, but because it gives 16 subnets, not because it gives excessive addresses.

There's no minimum subnet size.

/64 acts as a soft limit due to the prevalence of SLAAC. Which is good in a way, since it means ISPs have to give out at least /64, which means you're always able to subnet (although you can't use SLAAC and must use static addresses or DHCP) unlike IPv4 where you have to pay for extra addresses.

The purpose of SLAAC intends to have many customers in one /64 network though.

No, just many devices.

You can DoS your whole subnet by pretending to be a billion devices. In IPv4 you can do it by occupying all the IP addresses. Therefore putting several customers on one network is a bad idea, just like in IPv4.

The purpose of SLAAC is to make it "easy" for a client to get onto the network without something like a DHCP server tracking addresses. If you set it up, it generally just works.

Previously it worked by putting the MAC address in the last 64 bits.

Yes, that was before privacy extensions. It hasn't been like that (in most implementations) for a very long time.

And you get no privacy if /64 prefix is a stable identifier of one customer.

This doesn't seem like an IPv6-specific issue. For most broadband customers, your external IPv4 address is also generally stable. Mine hasn't changed in years.

Yes, you can't use SLAAC feature, but there's no subnetting limit in IPv6. Any subnet size works.

Writing to you from /72.

You're technically correct, but ISPs best practice is to hand out a /64.

That's not how you're supposed to use IPv6. It would just be 64 bits if that was the case. Instead, 99% of the time, it's a 64 bit subnet ID and a 64 bit device ID.

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