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Groups > alt.comp.software.firefox > #17884
| From | Brian Gregory <void-invalid-dead-dontuse@email.invalid> |
|---|---|
| Newsgroups | alt.comp.software.firefox, alt.os.linux, comp.mobile.android, alt.internet.wireless |
| Subject | Re: PSA: IPv6 browser privacy leaks are caused by the host yet there's a simple fix |
| Date | 2026-07-23 04:50 +0100 |
| Organization | https://www.Brian-Gregory.me.uk/ |
| Message-ID | <ncdhbpF5510U1@mid.individual.net> (permalink) |
| References | <113kg6k$s72$1@nnrp.usenet.blueworldhosting.com> <nccnmhF1b5nU1@mid.individual.net> <113ral7$5ji$1@nnrp.usenet.blueworldhosting.com> <113rlsg$397l4$1@dont-email.me> <113s0ft$n4n$1@nnrp.usenet.blueworldhosting.com> |
Cross-posted to 4 groups.
On 23/07/2026 04:06, Maria Sophia wrote: > agris wrote: >>> So there is a *lot* of good value which came of this IPv6 privacy >>> effort. Thanks again for not beating around the bush to let us know >>> what you think! >> >> You shouldn't disable IPv6. It is the current generation of Internet >> Protocol. Rather then disabling it just turn on IPv6 privacy. >> >> sysctl net.ipv6.conf.eth0.use_tempaddr = 2 >> >> If your VPN doesn't support IPv6 that's your VPN's problem. Switch to >> one that does. NAT was never intended as a privacy or security feature. >> When it set use_tempaddr to 2 you use different addresses for outgoing >> connections and those addresses expire after a certain (configurable) >> amount of time. Disabling IPv6 and only using a legacy protocol just >> because you don't understand it is like shooting yourself in the foot. >> Don't do it. > > This thread has been a learning experience for me & hopefully for others. > To be clear, I'll never disagree with a logically defensible viewpoint. > > While NAT was never a security feature and while IPv6 is a modern Internet > protocol, we must agree RFC 8981 privacy extensions exist for a reason. > > As you noted, RFC 8981 enabling of IPv6 Privacy Extensions generates > temporary, randomized outgoing addresses which rotate periodically. > sysctl net.ipv6.conf.eth0.use_tempaddr = 2 > > Meanwhile, the stable IPv6 address remains available for inbound > connections, but outbound traffic uses those ephemeral identities. . > > With that in mind, this is one of those technical debates where smart > people land on different sides because the trade-offs aren't trivial. > a. VPN leaks are a real, practical concern. > b. IPv6 privacy extensions aren't a magic shield. > c. Some users simply don't need IPv6 yet. > > Whether unilaterally disabling IPv6 is "shooting yourself in the foot" > depends on whether or not we need IPv6 in the first place. Do we? > > I would ask everyone here who cares about this topic to ask themselves... > Q1: Do you use any services, apps, or devices that require direct > inbound connections from the internet (such as hosting a game server, > running a self-hosting services, or accessing your network remotely)? > Q2: Do you ever use a VPN (either always, often, or occasionally) > for privacy, work, or bypassing geo-restrictions? > Q3: When you use VPNs, is your priority mainly IP obfuscation or security? > Q4: Does your ISP currently give you an IPv6 address? > Q5: Do you ever connect multiple devices through your home network > (PC, phone, tablet, smart TV, etc.) and care about them communicating > smoothly with each other (such as with file sharing, casting, local > streaming, or LAN gaming)? > Q6: Do you ever use modern devices or apps that require IPv6 to work > such as smart-home devices, peer-to-peer apps, or anything that > requires "IPv6 connectivity" in its settings? > > The point of these questions is to ascertain if we even need IPv6. > For example, > a. I do not host anything that needs IPv6 > b. I don't have apps that require IPv6 > c. My WISP doesn't even give me IPv6 > d. I bittorrent only through a VPN > e. When I switch networks (e.g., a hotspot) I only care about privacy > > So, in my case, IPv6 adds no value and only leaks my real identity. > Even if my ISP does not give me IPv6, my devices device (Windows, Linux, > Android, etc.) & browsers will still try to use IPv6 whenever possible. > > At home, IPv6 is NOT a privacy threat because there is nothing to leak. > > But when my device is *outside* my network (admittedly, that's for laptops > and phones), the device will happily use IPv6 which leaks our identities. > > When I go to the public library and connect my phone & laptop to their > Wi-Fi network, the laptop & phone get an IPv6 address which websites see. > > But the latter half of that IPv6 address is unique to the device! > However, when I just looked that up, I found something we haven't stated. > A. Android rotates temporary IPv6 addresses regularly > B. Windows 10/11 generates temporary IPv6 addresses by default > C. Most Linux variants enable IPv6 privacy extensions by default > > Android, Windows, and modern Linux all use temporary IPv6 addresses! > By default. > > Windows uses two timers: > a. Preferred lifetime (generally 24 hours) > b. Valid lifetime (generally 7 days) > > Android rotates temporary IPv6 addresses every 24 hours. > > Modern Linux distros ship with: > net.ipv6.conf.default.use_tempaddr = 2 > net.ipv6.conf.all.use_tempaddr = 2 > a. Preferred lifetime (generally 24 hours) > b. Valid lifetime (generally 7 days, but this isn't used in most Linux's) > > Since our IPv6 temporary address (RFC 8981) lasts ~24 hours, we're > trackable if we, for example visit the same network twice in a day. > > Two visits to the same website on the same day, from home, could be linked. > a. With IPv4 they know it's the same household. > b. With IPv6 they know it's the same device. > > Please correct me if I'm wrong, as the whole point is to understand IPv6. Sounds right. In theory you can change things so that RFC 8981 privacy addresses change more often, but I believe it isn't often simple to do and can cause unexpected problems in certain situations. Plus, of course, it has to be done once on each device you want to keep private. -- Brian Gregory (in England).
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PSA: IPv6 browser privacy leaks are caused by the host yet there's a simple fix Maria Sophia <mariasophia@comprehension.com> - 2026-07-20 02:45 -0400
Re: PSA: IPv6 browser privacy leaks are caused by the host yet there's a simple fix "Carlos E. R." <robin_listas@es.invalid> - 2026-07-20 14:03 +0200
Re: PSA: IPv6 browser privacy leaks are caused by the host yet there's a simple fix Maria Sophia <mariasophia@comprehension.com> - 2026-07-21 02:43 -0400
Re: PSA: IPv6 browser privacy leaks are caused by the host yet there's a simple fix "Carlos E. R." <robin_listas@es.invalid> - 2026-07-21 11:18 +0200
Re: PSA: IPv6 browser privacy leaks are caused by the host yet there's a simple fix Maria Sophia <mariasophia@comprehension.com> - 2026-07-21 07:36 -0400
Re: PSA: IPv6 browser privacy leaks are caused by the host yet there's a simple fix "Carlos E. R." <robin_listas@es.invalid> - 2026-07-21 19:28 +0200
Re: PSA: IPv6 browser privacy leaks are caused by the host yet there's a simple fix Maria Sophia <mariasophia@comprehension.com> - 2026-07-21 14:32 -0400
Re: PSA: IPv6 browser privacy leaks are caused by the host yet there's a simple fix Hank Rogers <Hank@nospam.invalid> - 2026-07-21 18:31 -0500
Re: PSA: IPv6 browser privacy leaks are caused by the host yet there's a simple fix Maria Sophia <mariasophia@comprehension.com> - 2026-07-22 15:40 -0400
Re: PSA: IPv6 browser privacy leaks are caused by the host yet there's a simple fix Maria Sophia <mariasophia@comprehension.com> - 2026-07-22 18:53 -0400
Re: PSA: IPv6 browser privacy leaks are caused by the host yet there's a simple fix Brian Gregory <void-invalid-dead-dontuse@email.invalid> - 2026-07-28 00:36 +0100
Re: PSA: IPv6 browser privacy leaks are caused by the host yet there's a simple fix David Higton <dave@davehigton.me.uk> - 2026-07-20 20:47 +0100
Re: PSA: IPv6 browser privacy leaks are caused by the host yet there's a simple fix "Carlos E. R." <robin_listas@es.invalid> - 2026-07-20 21:59 +0200
Re: PSA: IPv6 browser privacy leaks are caused by the host yet there's a simple fix Maria Sophia <mariasophia@comprehension.com> - 2026-07-21 02:04 -0400
Re: PSA: IPv6 browser privacy leaks are caused by the host yet there's a simple fix "Adam H. Kerman" <ahk@chinet.com> - 2026-07-21 06:37 +0000
Re: PSA: IPv6 browser privacy leaks are caused by the host yet there's a simple fix Maria Sophia <mariasophia@comprehension.com> - 2026-07-21 03:23 -0400
Re: PSA: IPv6 browser privacy leaks are caused by the host yet there's a simple fix Nuno Silva <nunojsilva@invalid.invalid> - 2026-07-21 07:59 +0100
Re: PSA: IPv6 browser privacy leaks are caused by the host yet there's a simple fix Maria Sophia <mariasophia@comprehension.com> - 2026-07-21 04:41 -0400
Re: PSA: IPv6 browser privacy leaks are caused by the host yet there's a simple fix "Carlos E. R." <robin_listas@es.invalid> - 2026-07-21 11:03 +0200
Re: PSA: IPv6 browser privacy leaks are caused by the host yet there's a simple fix Maria Sophia <mariasophia@comprehension.com> - 2026-07-21 05:47 -0400
Re: PSA: IPv6 browser privacy leaks are caused by the host yet there's a simple fix "Carlos E. R." <robin_listas@es.invalid> - 2026-07-21 12:27 +0200
Re: PSA: IPv6 browser privacy leaks are caused by the host yet there's a simple fix Maria Sophia <mariasophia@comprehension.com> - 2026-07-21 14:10 -0400
Re: PSA: IPv6 browser privacy leaks are caused by the host yet there's a simple fix "Carlos E. R." <robin_listas@es.invalid> - 2026-07-21 10:53 +0200
Re: PSA: IPv6 browser privacy leaks are caused by the host yet there's a simple fix Maria Sophia <mariasophia@comprehension.com> - 2026-07-21 05:19 -0400
Re: PSA: IPv6 browser privacy leaks are caused by the host yet there's a simple fix "Carlos E. R." <robin_listas@es.invalid> - 2026-07-21 11:30 +0200
Re: PSA: IPv6 browser privacy leaks are caused by the host yet there's a simple fix Maria Sophia <mariasophia@comprehension.com> - 2026-07-21 06:10 -0400
Re: PSA: IPv6 browser privacy leaks are caused by the host yet there's a simple fix Maria Sophia <mariasophia@comprehension.com> - 2026-07-22 19:13 -0400
Re: PSA: IPv6 browser privacy leaks are caused by the host yet there's a simple fix Nuno Silva <nunojsilva@invalid.invalid> - 2026-07-22 09:47 +0100
Re: PSA: IPv6 browser privacy leaks are caused by the host yet there's a simple fix Maria Sophia <mariasophia@comprehension.com> - 2026-07-22 16:30 -0400
Re: PSA: IPv6 browser privacy leaks are caused by the host yet there's a simple fix Brian Gregory <void-invalid-dead-dontuse@email.invalid> - 2026-07-22 21:35 +0100
Re: PSA: IPv6 browser privacy leaks are caused by the host yet there's a simple fix Maria Sophia <mariasophia@comprehension.com> - 2026-07-22 16:46 -0400
Re: PSA: IPv6 browser privacy leaks are caused by the host yet there's a simple fix Brian Gregory <void-invalid-dead-dontuse@email.invalid> - 2026-07-23 04:33 +0100
Re: PSA: IPv6 browser privacy leaks are caused by the host yet there's a simple fix Nuno Silva <nunojsilva@invalid.invalid> - 2026-07-23 08:12 +0100
Re: PSA: IPv6 browser privacy leaks are caused by the host yet there's a simple fix Maria Sophia <mariasophia@comprehension.com> - 2026-07-23 16:23 -0400
Re: PSA: IPv6 browser privacy leaks are caused by the host yet there's a simple fix Oregonian Haruspex <no_email@invalid.invalid> - 2026-07-25 04:58 +0000
Re: PSA: IPv6 browser privacy leaks are caused by the host yet there's a simple fix Maria Sophia <mariasophia@comprehension.com> - 2026-07-26 14:25 -0700
Re: PSA: IPv6 browser privacy leaks are caused by the host yet there's a simple fix Maria Sophia <mariasophia@comprehension.com> - 2026-07-21 01:38 -0400
Re: PSA: IPv6 browser privacy leaks are caused by the host yet there's a simple fix Nuno Silva <nunojsilva@invalid.invalid> - 2026-07-21 07:51 +0100
Re: PSA: IPv6 browser privacy leaks are caused by the host yet there's a simple fix Maria Sophia <mariasophia@comprehension.com> - 2026-07-21 03:45 -0400
Re: PSA: IPv6 browser privacy leaks are caused by the host yet there's a simple fix Nuno Silva <nunojsilva@invalid.invalid> - 2026-07-22 09:37 +0100
Re: PSA: IPv6 browser privacy leaks are caused by the host yet there's a simple fix Maria Sophia <mariasophia@comprehension.com> - 2026-07-24 11:36 -0700
Re: PSA: IPv6 browser privacy leaks are caused by the host yet there's a simple fix Brian Gregory <void-invalid-dead-dontuse@email.invalid> - 2026-07-22 21:32 +0100
Re: PSA: IPv6 browser privacy leaks are caused by the host yet there's a simple fix Maria Sophia <mariasophia@comprehension.com> - 2026-07-22 16:54 -0400
Re: PSA: IPv6 browser privacy leaks are caused by the host yet there's a simple fix agris <agris@invalid.tld> - 2026-07-22 17:05 -0700
Re: PSA: IPv6 browser privacy leaks are caused by the host yet there's a simple fix Maria Sophia <mariasophia@comprehension.com> - 2026-07-22 23:06 -0400
Re: PSA: IPv6 browser privacy leaks are caused by the host yet there's a simple fix Brian Gregory <void-invalid-dead-dontuse@email.invalid> - 2026-07-23 04:50 +0100
Re: PSA: IPv6 browser privacy leaks are caused by the host yet there's a simple fix Maria Sophia <mariasophia@comprehension.com> - 2026-07-23 16:51 -0400
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