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 🏳️‍⚧️   θΔ ⋐ & ∞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 threadJuli Jane
@karotte @tauon What else they could have done? Well maybe implement some logic which does not make any use of colons in a path impossible. It would be quite clear in this use case that it can't be meant as a drive name.
Jul 18, 2025 at 5:16pmWeb
Show thread🌸 lily 🏳️‍⚧️   θΔ ⋐ & ∞Jul 18, 2025
@julijane @karotte it's too late for that
Show threadWladimir PalantJul 18, 2025
@julijane @karotte @tauon They probably missed their chance back when UNC paths were introduced. And now way too much software depends on UNC paths being structured in a particular way, breaking backwards compatibility is an absolute no-go. You have to wait for Microsoft to introduce yet another path type, might even happen within your lifetime.
Show threadJernej Simončič �Jul 18, 2025
@julijane @karotte @tauon Colons are also used as a separator for NTFS named streams…
Show threadGe0rG ➡️ Easter-H-EggJul 19, 2025
@julijane
But that would break all the legacy programs using `strtok(..., ":")` to separate the driver letter! It's a CON!
@karotte @tauon