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Comment by adgjlsfhk1 | Hacker News Reader

what do you mean by topology? the only information leaked would be the number of computers making requests.

that's not even true with slaac temporary (a.k.a privacy) or secured addresses.

the only thing you'd "leak" is the prefix, which is no different than a IPv4 WAN address that you'd get with a v4 NAT.

And what computer is making what requests. Now that i think about it, this cloud be the reason why youtube started making recommendations based on stuff i just watched in private browser tabs...

I have multiple computers in the house, mostly not logged in to Google. YouTube recommendations spill between devices all the time - like, if I watch a video on one device, I’ll see the same video recommended on another. Or if my partner watches something, YouTube will recommend it to me.

They’re obviously doing recommendations based on IP address. (And this is purely over ipv4).

> They’re obviously doing recommendations based on IP address. (And this is purely over ipv4).

I have IPv6 at home and connect to Youtube over IPv6 (that's generally the default behaviour on macOS and many other OSes). I reboot my DSL modem-router every night and get a new IPv4 address and new IPv6 prefix every day.

Now: I live in Ontario, and my ISP is based in Ontario, but they serve clients in Quebec. Every so often, when surfing Youtube, I get served ads in French because according to my (IPv6) address I am "in" Quebec.

And, while I am not logged into any Google service, I do not block cookies. So even with cookies, Youtube seems to be fairly dumb about serving ads correctly just based on IP addresses (or at least IPv6 addresses and/or IPv6 prefixes), since cookies don't seem to be useful.

So I'm not quite sure about what people are talking about when they say "IPv6 tracking" if even Google/Youtube can't get their act together.

I live just outside London and have been wondering why I’ve been getting ads from More4 for Wales and Cardiff.

Iechyd Da!

> They’re obviously doing recommendations based on IP address

eBay uses IPs showing content, too. I see 'items you've viewed recently' show items I've never looked at, since when on a mobile connection my IP changes fairly frequently and eBay carries over the recently viewed state from whoever else was previously using that IP.

It had puzzled me until I came across this[1] eBay topic where others had experienced this, from shared offices to spouses, etc.

[1] https://community.ebay.com/t5/Share-eBay-Technical-Issues/Re...

Look at what Android does with MAC address randomization on wireless networks. We will probably see something similar with IPv6.

> We will probably see something similar with IPv6.

It's been available for some time: https://www.internetsociety.org/resources/deploy360/2014/pri...

On my macOS system, I currently have four IPv6 IPs (excluding the link-local IP), all of which are random.

Not just Android. My laptop does it too (NetworkManager). That's just IPv4 on devices designed to travel so it seems a fair thing to do. Bloody pain to diagnose why a static DHCP lease isn't working the first time, after that you find the mechanisms to turn it off. Nearly everything does it for IPv6, for a given value of everything!

For decades we have generally allowed all outbound and worried and fretted about and filtered inbound. I think it is time for us all to get a grip and do the job properly. However, with the delights of DNS over http and the like, the horse has not only bolted but has a new paint job, far better shoes than you can afford, eats grass that was prepared by a Michelin starred chef and belongs to someone else now.

We all need to be far more sophisticated about how traffic (knowledge/ideas/data) flows in and out of our networks/lives. Packet filtering is just one tool in the box and worrying about an addressing scheme being global (IPv6) instead of a weird hybrid (IPv4) is completely missing the real issue stabbing you in the nadgers.

That's a very strong claim to make. I'd appreciate if you could provide a source to that statement!

Your chrome build id is available in both areas. Not really a secret.

I'd be really surprised if I've got a chrome build ID on my browser.

That is information about the topology.

It's fairly limited, without a lot of time and effort, or information from inside the network. I assume you're not acting as an AS, doing BGP, etc; and that you're just getting an IP allocation from a single ISP. In that case, you're probably getting an entire IPv6 subnet (like a /48) allocated to you. Ideally, you make the entire subnet available to your systems.

Assuming you block unsolicited packets (that is, packets not related to existing connections/streams) at your border (the connection to your ISP), then outsiders won't be able to use tools like traceroute to learn anything. All that an outsider has is an IPv6 IP, and since you're not doing BGP with anything, all they'll know to do is to send the traffic to your ISP.

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