alt Hacker NewsWow. It's like your reply is doing an impression of IPv6! (I'm just teasing. I hope you are having a happy new year.)
Not GP, but:
> What happens when multiple devices in your /8 want to listen on port 80 and 443 on the public address? Only one of them can. Now you're running a proxy.
I don't want any of my devices listening on the public address, much less multiple.
> It's called a firewall. You want a firewall. IPv6 also has a firewall. NAT is not a firewall. NAT is usually configured as part of your firewall, but is not a firewall.
That's a non sequitur. I can have a both a firewall and a NAT. The two layers are better than one because at least my address is shouldn't be routable even if I failed to configure my firewall correctly.
> DHCPv6 Okay? DHCPv4
> What are you supposed to do with a /8? Do you have several million computers? That's GP's point. Running out of address space is not a problem even on IPv4 with NAT.
> What happens if your ISP changes your IPv4 address? Well, an ostensible advantage of IPv6 is publicly routable addresses. I know how to configure my internal IPv4 network with host table entries and so on. If I move to IPv6 then my "internal" network address space is at the whim of my ISP.
Replies
A NAT is part of a firewall, not a separate thing, so if the firewall is misconfigued, then your NAT may not be working either.
On not running out of (private) IPs, I guess you've never had the fun of having to deal with overlapping ranges (because it isn't the number of IPs that's the issue, it's how the ranges are allocated). While this can still happen on IPv6, there are so many more subnets that this is far less likely.
Also, a key thing that IPv6 makes obvious (which is also true to some extent of IPv4, but that most systems try to avoid showing) is that each link can have multiple IPs (there will be at least one link-local address), and so while your ISP can provide you a public range, you don't need to use it if you do not want to, you can always use an Unique Local Address (ULA - https://en.wikipedia.org/wiki/Unique_local_address), which reduce the chance of overlapping ranges.
>If I move to IPv6 then my "internal" network address space is at the whim of my ISP.
This is a major problem to me before I'd go wholesale IPv6 at home as the primary way I address and connect to hosts
I have IPv6 enabled, but it's just all defaults. My traffic is going out over the internet on IPv6, my home automation stuff in the house using Matter is on IPv6, but for the few server-types that I have in the house they are still identifiable by me by their IPv4, and my addressing to get into my network from outside is via my ISP's IPv4 address
There really needs to be a universal way to bring IPv6 addresses to your ISP, so they're portable like a phone number. Both so that I can take them with me if I switch providers and so that my ISP can't arbitrarily change them from underneath me
> That's a non sequitur. I can have a both a firewall and a NAT. The two layers are better than one because at least my address is shouldn't be routable even if I failed to configure my firewall correctly.
You have two layers of indirection and one layer of security. If you failed to configure your firewall correctly, you would be better off without NAT because you would become aware of it quicker and not rely on NAT.
NAT doesn't really do anything other than address conservation because of NAT-punching techniques like STUN/TURN/UPnP, which are nessisary because NAT's features are bugs.
> That's a non sequitur. I can have a both a firewall and a NAT. The two layers are better than one because at least my address is shouldn't be routable even if I failed to configure my firewall correctly.
You talk about NAT like it's a single thing: it is not. There are at least three major varieties of NAT:
* https://blog.ipspace.net/2011/12/is-nat-security-feature/
See also various 'cones' that add complexity to getting things to work (and for which kludges like ICE/TURN/etc had to be invented):
* https://en.wikipedia.org/wiki/Network_address_translation#Me...
See also RFC 4787 which distinguishes between NAT mapping and NAT filtering. Also, also see perhaps "NAT Traversal Mess":
> Well, an ostensible advantage of IPv6 is publicly routable addresses. I know how to configure my internal IPv4 network with host table entries and so on. If I move to IPv6 then my "internal" network address space is at the whim of my ISP.
This is not quite correct. You have two simple options for avoiding this: DNS and SLAAC. By giving all of your hosts dns names you don’t have to care about the individual addresses much. If they change just update the dns zone.
The second is to configure a Unique Local Address for each host using SLAAC. Have your router announce a prefix inside of fd00::/7 so that every one of your computers ends up with a private address as well as the public one. This is like using a reserved private address in IPv4, such as 10.0.0.0/8, except that there are a lot more possible networks. There is only one 10.0.0.0/8, but the convention with IPv6 ULAs is to generate 40 random bits and use them to make a /40. Add 16 more bits for a subnet id to create a /64 that your router will advertise as a prefix. This is probably overkill for most of us, but it does enable us to merge networks without causing address collisions. You can keep using them no matter what happens. Even changing ISP won't change these addresses.
Of course the third option is to buy IP transit service instead of internet access service. You can then go to your local RIR and ask them to assign you your own address block. Announcing that address block using BGP gives you a permanent block of routable addresses that follows you from ISP to ISP. But most people find that to be a bit of a hassle compared to consumer–grade internet service.
> I can have a both a firewall and a NAT. The two layers are better than one because at least my address is shouldn't be routable even if I failed to configure my firewall correctly.
That's not true. When you configure just NAT (with e.g. nftables on Linux), the NATed devices are still reachable from the outside, you just have to add an entry to your routing table to reach that internal address space using the router.
The RFC for NAT was extremely specific: this was only about creating more addresses, NOT security.
Because your devices are routable. You can’t be on the Internet without an IP. They just have some ephemeral addresses. But randomizing port numbers (that is NAT) is not a good security mechanism.
Just FYI you can do ULA + NAT with IPv6 and get the same thing as RFC1918 + NAT on v4.
>I don't want any of my devices listening on the public address, much less multiple.
That is good for you, but given the option between an address scheme that requires a proxy and one that does not, I would prefer the latter.
>I can have a both a firewall and a NAT. The two layers are better than one because at least my address is shouldn't be routable even if I failed to configure my firewall correctly.
Why? NAT is a network tool. Firewall is a security control.
>I don't want any of my devices listening on the public address, much less multiple.
If you don't listen to public ports on IPv4, then there is no point in touting any of the benefits of IPv4. Even if you think NAT is good, you're not using it in the first place so why care about it?
You basically ruined your entire case with that sentence.
Great response. Your last point is particularly convincing and I never thought of it before. Even better, what happens if you use a failover WAN on your router?
> I don't want any of my devices listening on the public address, much less multiple.
Just because you don't shouldn't mean other people get denied this.
Been having a nice break over the new year, thank you :)
I can't argue with sticking on IPv4 when you have no need for IPv6. However, people saying no NAT means no firewall really bothers me because it's just wrong and usually gets thrown around as part of a point around "who needs IPv6 anyway".
The two layers IMO don't make a practical difference. A deny by default firewall will fail closed, unless poorly configured. A poorly configured firewall for IPv4 with NAT can still leave machines exposed. This is not an IPv4/IPv6 problem this is down to your router. However you do expose what used to be private addresses with IPv6, but there's not much to do with the address that couldn't be done with your IPv4 address assuming sane firewalls that both stacks run.
On the other side of the coin IPv6 being ubiquitous would make my life much easier. I self host a few things across a few different machines. IPv6 offers me a much simpler solution, both to managing firewalls and not needing to fight over port 80/443, but also because I can't get a public IPv4 address from my ISP without spending ungodly amounts of money. They support IPv6 but many of the services I host don't support it. I have to use a second site + machine, wireguard tunnels, and nginx socket proxies to expose stuff publicly (this is cheaper than the public IPv4 address from my ISP).
My point about DHCPv6 is to say that if you want to use DHCP in IPv6 you can. It's right there, it's just not the default.
IPv6 doesn't make things substantially harder, just different. But people don't want to learn new things because, to be fair, they don't need them. But people who do need IPv6 are stuck behind garbage ISPs and this "not my problem" attitude throwing around ignorant arguments. Complaints about long addresses really get me too :), use a DNS.