LukasJul 18, 2025

Mildly cursed factoid about UNC paths:

- UNC Paths can contain IP addresses such as \\192.168.1.1\share
- IPv6 addresses are supported as well
- IPv6 addresses contain colons
- can't have colons in Windows paths since colons are reserved for drive letters

So Microsoft came up with the the ipv6-literal.net domain that's special-cased by Windows so you can to write IPv6 addresses in UNC paths as 2a0e-3c0--21.ipv6-literal.net without it hitting any resolvers.

Show thread🌸 lily πŸ³οΈβ€βš§οΈ   ΞΈΞ” ⋐ & ∞Jul 18, 2025
@karotte why did they do it like that ​​
Show threadLukasJul 18, 2025

@tauon I mean, what else could they have done? I agree that the solution is a bit bonkers, but I don't immediately see any other viable solutions that don't conflict with anything else.

They could at least held on to the ipv6-literal.net domain.

Show thread🌸 lily πŸ³οΈβ€βš§οΈ   ΞΈΞ” ⋐ & ∞
@karotte
- changed unc parsing to support ipv6 (perhaps \\[2a0e-3c0--21]\share?)
- i was going to say use ip6.arpa but those don't seem to require AAAA records that point to the requested ip so that's not an option
- use a different domain that's not ipv6-literal.net that won't ever be resolved (i forget in what circumstances underscores are allowed, but 2a0e-3c0--21._ip6?)
- probably something better that i'm not realising
Jul 18, 2025 at 5:21pmWeb