IPv6 can "leak" MAC addresses of connected devices "behind the firewall" if you don't have the privacy extensions / random addresses in use.

There are a number of footguns for privacy with IPv6 that you need to know enough to avoid.

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craftkiller 2 days ago | parent | next [-]

Privacy extensions are enabled by default on OSX, windows, android, and iOS: https://ipv6.net/guide/mastering-ipv6-a-complete-guide-chapt...

On Linux, I think the defaults are left up to the distros so there is a chance of a privacy footgun there. Hopefully most distros follow the example set by Apple and Microsoft (a sentence I never thought I would write...)

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bombcar 2 days ago | parent [-]

They are now - I'm not sure when they implemented them but I know Windows at least would do some really stupid stuff very early on.

	▲	Guvante 2 days ago \| parent [-]
		Aren't we talking about now? No one is saying we should have activated IPv6 in its first iteration.

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zekica 2 days ago | parent | prev [-]

All desktop/mobile OSes today use "Stable privacy addresses" for inbound traffic (only if you are hosting something long-term) and "Temporary addresses" for outbound traffic and P2P (video/voice calls, muliplayer games...) that change quickly (old ones are still assigned to not break long-lived connections but are not used for new ones).