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Re:I spent a week without IPv4 to understand IPv6 transition... by mavhc on Monday March 06, 2023 @10:57AM (#35042540)
NAT and a Firewall are two different concepts.

What's wrong with a firewall that blocks everything by default, yet all your devices have a public IP?

Re:I spent a week without IPv4 to understand IPv6 transition... by r3trohack3r on Monday March 06, 2023 @11:27AM (#35042926)
> NAT and a Firewall are two different concepts.

They are, but in practice they are muddled together and I suspect people are going to create subnets with IPv6 in the name of security. In IPv4 NAT is used to make sure your laptop isn't exposed to random script kiddies trying to scan for vulnerable services behind your router. A fun exercise is to plug a RaspberryPi up directly to a public facing IP address and log every packet it receives. Then give those scripts a few services to detect (HTTP server, SSH server, etc.) and look at how the traffic shifts from scanning for ports to scanning for vulnerabilities. Being connected directly to the public internet is a real eye opening experience.

I do believe future IPv6 networks will have gateway machines and/or bastions that are connected to the public internet with public IPv6 addresses. And then they'll have an interior network that they use NAT for. Individual machines will not be routable or discoverable without going through a bastion/gateway that explicitly controls the flow of traffic into a network. Not because this is the ideal way to structure an IPv6 network, but because this pattern is going to carry over from the IPv4 world and there is a lot of momentum in tribal knowledge using NAT as a form of firewall.

Re:I spent a week without IPv4 to understand IPv6 transition... by Arnavion on Monday March 06, 2023 @04:22PM (#35047785)
>In IPv4 NAT is used to make sure your laptop isn't exposed to random script kiddies trying to scan for vulnerable services behind your router.

NAT does nothing for that. Those incoming connections are dropped on the WAN interface before NAT would even be involved. Which is why it works exactly the same way regardless of whether the destination IP for that traffic was IPv4 or IPv6.

Re:I spent a week without IPv4 to understand IPv6 transition... by CircleSpokes on Monday March 06, 2023 @07:58PM (#35050091)
>In IPv4 NAT is used to make sure your laptop isn't exposed to random script kiddies trying to scan for vulnerable services behind your router. A fun exercise is to plug a RaspberryPi up directly to a public facing IP address and log every packet it receives. Then give those scripts a few services to detect (HTTP server, SSH server, etc.) and look at how the traffic shifts from scanning for ports to scanning for vulnerabilities. Being connected directly to the public internet is a real eye opening experience.

That isn't really feasible with IPV6 though is it? The smallest IPV6 subnet is 18,446,744,073,709,551,616 addresses, so even if you setup a Pi fully open to the world with default passwords the chance of someone scanning it is basically zero. That type of scanning only works because the IPV4 range is so small (& you can efficiently ignore large parts of it like the US DOD space, private addresses, etc).

Re:I spent a week without IPv4 to understand IPv6 transition... by bauruine on Monday March 06, 2023 @09:10PM (#35050634)
Yes at the moment the IPv6 internet is way more secure even without a firewall but there are possible attacks to enumerate the used IPv6 addresses. [0]

[0]: https://isc.sans.edu/diary/Targeted+IPv6+Scans+Using+pool.nt...

Re:I spent a week without IPv4 to understand IPv6 transition... by waych on Monday March 06, 2023 @11:00AM (#35042594)
Maybe you don't want to reveal your internal infrastructure to the world? Seems like basic opsec.
Re:I spent a week without IPv4 to understand IPv6 transition... by RealStickman_ on Monday March 06, 2023 @11:02AM (#35042619)
There's no chance of anybody guessing your infrastructure just by looking at your subnet. (Minimum is /64, which is HUGE!)
Re:I spent a week without IPv4 to understand IPv6 transition... by waych on Monday March 06, 2023 @11:27AM (#35042923)
Every packet leaving an IPv6 network that isn't NATed has an effective node ID in the packet. No need to guess just look at the packets.
Re:I spent a week without IPv4 to understand IPv6 transition... by bityard on Monday March 06, 2023 @11:33AM (#35042998)
Most devices support privacy extensions (temporary v6 addresses) for this exact reason. https://www.rfc-editor.org/rfc/rfc4941
Re:I spent a week without IPv4 to understand IPv6 transition... by waych on Monday March 06, 2023 @11:49AM (#35043229)
This helps mitigate correlations over time but doesn't do anything to mask the identity of the node within a given refresh interval (default one day).
Re:I spent a week without IPv4 to understand IPv6 transition... by jlokier on Monday March 06, 2023 @03:58PM (#35047490)
Those IPv6 privacy extensions still reveal when the same node connects to a sequence of destinations within the address change interval, though. E.g. observers can see a single device connects to Facebook, OnlyFans, Pornhub and PayPal in that order.

Behind a NAT, observers can only make that connection (using only addresses) for the network as a whole, instead of an individual device on the network. So the privacy extensions are weaker than NAT

(If the IPv6 privacy extensions used a different address for each connection, they would be more like NAT in this regard.)

That said, other observable clues still allow connections from a single device to be associated, NAT or not. There's TCP OS fingerprinting for example, and the close timing of related connections.

Re:I spent a week without IPv4 to understand IPv6 transition... by bert64 on Tuesday March 07, 2023 @09:33AM (#35055744)
That requires someone who has the ability to monitor all your traffic - ie the government, your ISP, or a hacker who has infiltrated one of those two.

In this scenario it's a lot more work trying to map out your infrastructure than to try performing a MITM connection against some of your outbound traffic.

Re:I spent a week without IPv4 to understand IPv6 transition... by justeleblanc on Monday March 06, 2023 @11:49AM (#35043218)
Your machines could change their IPs for every second of every day and you wouldn't come close to exhausting your /64 subnet for the next billion years.
Re:I spent a week without IPv4 to understand IPv6 transition... by waych on Monday March 06, 2023 @11:55AM (#35043308)
The limit of changing addresses once every N seconds as N approaches 0 is equal to offline.

With any usable N, a clever observer would still easily work out what you were doing and still map out your infrastructure.

Re:I spent a week without IPv4 to understand IPv6 transition... by justeleblanc on Monday March 06, 2023 @12:42PM (#35044380)
What kind of observer is 1. able to listen to the entirety of your network's outside communications, 2. interested at all in it, 3. harm you only on the condition that they "map out" your internal infrastructure? This isn't a novel, the goal is not to solve intricate security non-problems.
Re:I spent a week without IPv4 to understand IPv6 transition... by waych on Monday March 06, 2023 @03:16PM (#35046971)
"The network is secure" is a common fallacy.
Re:I spent a week without IPv4 to understand IPv6 transition... by justeleblanc on Monday March 06, 2023 @04:11PM (#35047665)
"Those who don't know what to say quote adages" is a common saying.
Re:I spent a week without IPv4 to understand IPv6 transition... by __d on Monday March 06, 2023 @06:34PM (#35049410)
A common saying that ... invalidates itself?
Re:I spent a week without IPv4 to understand IPv6 transition... by waych on Monday March 06, 2023 @10:11PM (#35051071)
??

There is a whole industry built around network traffic analysis.

What makes you think it doesn't happen on the internet?

Re:I spent a week without IPv4 to understand IPv6 transition... by Spivak on Monday March 06, 2023 @05:26PM (#35048641)
Your ISP, "mapping your network" means being able to take data that was previously an amalgam of a household and reliably split it into the individual members and devices for better targeting.
Re:I spent a week without IPv4 to understand IPv6 transition... by kmbfjr on Monday March 06, 2023 @09:23PM (#35050736)
Take a moment and learn about Nokia’s Deepfield or Kintec.

The ISPs have the ability to see what is on your network by IPv4 egress. They have been able to do this for a decade.

Worrying that an IPv6 address divulges the network forgets that IPv4 devices betray their existence through DNS, their destinations and other network behavior.

The ISPs know.

Re:I spent a week without IPv4 to understand IPv6 transition... by justeleblanc on Tuesday March 07, 2023 @03:54AM (#35053170)
Unless you're part of the tiny percent of people who run their own router, your ISP can just monitor what goes through your ISP-provided router.
Re:I spent a week without IPv4 to understand IPv6 transition... by zamnos on Tuesday March 07, 2023 @04:07AM (#35053252)
With the home router+wifi market estimated to be USD 2070.43 million in 2022, I wouldn't say it's a tiny percentage of people, just people you know.
Re:I spent a week without IPv4 to understand IPv6 transition... by justeleblanc on Tuesday March 07, 2023 @05:55AM (#35053918)
1. Where does this stat come from?

2. You can't say anything about the percentage with just the absolute market value. At the very least you need something else to compare it too.

Please, be serious.

Re:I spent a week without IPv4 to understand IPv6 transition... by zamnos on Tuesday March 07, 2023 @09:50PM (#35064596)
A reader who's actually interested in getting the source, might try Googling for "2070.43", or even "2070.43 million wifi". I must admit, I wasn't serious enough about my comment to spend $3,250 on the whole report, and had to go off of the public preview. Since you seem to be more serious, maybe you could pay the $4,400 for a multi-user licensed copy of the report and share the PDF with me? I'd love to read more of the analysis.

So, I mean, I dunno, 2 billion dollars seems serious to me, but maybe we just have different barometers for what counts as "serious amounts of money". Especially considering these devices that are like $300.

Finally, might I remind you of the guidelines? in particular:

> When disagreeing, please reply to the argument instead of calling names. "That is idiotic; 1 + 1 is 2, not 3" can be shortened to "1 + 1 is 2, not 3."

https://news.ycombinator.com/newsguidelines.html

Re:I spent a week without IPv4 to understand IPv6 transition... by bert64 on Tuesday March 07, 2023 @09:36AM (#35055781)
Most people don't buy their own router, the ISPs bulk buy thousands of routers at a time. The ISPs make up most of the market.

Many of these routers are managed by the ISP using protocols such as TR-069, several ISPs have already been found to not only manage the devices but also monitor certain data including what devices are present.

Re:I spent a week without IPv4 to understand IPv6 transition... by JohnFen on Tuesday March 07, 2023 @03:03PM (#35060432)
This is pure anecdata, but almost everyone I know, include the people who aren't particularly computer-savvy, owns their own router and cable modem so that they don't have to pay a rental fee to their ISP.
Re:I spent a week without IPv4 to understand IPv6 transition... by nske on Wednesday March 08, 2023 @08:24AM (#35068682)
I don't think charging rent for consumer broadband equipment is common in many countries, at least not in Europe.
Re:I spent a week without IPv4 to understand IPv6 transition... by ianburrell on Monday March 06, 2023 @12:23PM (#35043860)
Why would changing N seconds break network? It would presumably keep active addresses until connections finish. IPv6 requires supporting multiple addresses per interface.

More reasonable is to use new address for each connection. Then nobody can tell if 10 addresses and 10 connections are one device or ten.

Re:I spent a week without IPv4 to understand IPv6 transition... by waych on Monday March 06, 2023 @12:38PM (#35044301)
This looks like NAT pushed down to the endpoint itself.

You've saved the translation in the router, but now routing lookups and ARP caches have grown by TEMP_VALID_LIFETIME / TEMP_PREFERRED_LIFETIME.

What are valid values in the scenario you are proposing? The defaults are 1 week / 1 day, so 7X. If you chose to rotate each second, and say allowed addresses to only be valid for say 20 minutes, this still appears to be a ~1200X blowup in routing overheads.

Re:I spent a week without IPv4 to understand IPv6 transition... by kazen44 on Monday March 06, 2023 @03:56PM (#35047469)
> You've saved the translation in the router, but now routing lookups and ARP caches have grown by TEMP_VALID_LIFETIME / TEMP_PREFERRED_LIFETIME.

They have not?

The global routing table size for ipv6 at max is a /32 (if i remember correctly) every customer gets a /56 prefix to use in their network, so the routing table entry would still be the same, no matter how many addresses you use to cycle through in your /64.

ARP caches do not exist in IPv6, and Neighbour discovery does not have the same "cache" mechanism as ARP does, it uses an entirely different mechanism for neighbour discovery. (which is also far more lightweight considering it is using multicast, compared to the broadcast of ARP).

Re:I spent a week without IPv4 to understand IPv6 transition... by waych on Monday March 06, 2023 @09:49PM (#35050937)
I don't understand what you mean. Neighbor Discovery Caches certainly are a thing.
Re:I spent a week without IPv4 to understand IPv6 transition... by mavhc on Monday March 06, 2023 @11:34AM (#35043003)
The whole world? How would that happen?
Re:I spent a week without IPv4 to understand IPv6 transition... by waych on Monday March 06, 2023 @11:57AM (#35043352)
Not the whole world. Just the world is sufficient.
Re:I spent a week without IPv4 to understand IPv6 transition... by wjholden on Monday March 06, 2023 @11:53AM (#35043285)
For HTTP/HTTPS, proxy servers (forward and reverse) offer an equivalent ability to hide addresses and a lot more features for security and performance.
Re:I spent a week without IPv4 to understand IPv6 transition... by op00to on Monday March 06, 2023 @05:15PM (#35048516)
Someone might know your IP, and somehow that information is delicious and irresistible to evil .. uh .. spammers?
Re:I spent a week without IPv4 to understand IPv6 transition... by CaliforniaKarl on Monday March 06, 2023 @06:37PM (#35049457)
In that case, have your system use a random IP.

Right now, my macOS system has four publicly-routable IPv6 IPs, all random. New ones are generated, and old ones removed, regularly.

https://www.internetsociety.org/resources/deploy360/2014/pri...