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Comment by usr1106 | Hacker News Reader

    ssh 64:ff9b::1.3.3.7

What address syntax is that? I mean I can easily guess what it means, but I wasn't aware such mixture exists. Do connect(2) and friends support that?

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It's an IPv4-mapped IPv6 address. Just interpret the IPv4 address like it's the last 32 bits of the v6 address.

In the example, 64:ff9b::103:307 is equivalent. A more complicated example might be akin to 64:ff9b::198.51.100.231, equivalent to 64:ff9b::c633:64e7.

Thank you very much for this question. I've rewrote and improve my article to cover exactly this topic: https://pavel.network/building-gateway-to-access-legacy-ipv4...

It's an RFC6052 address.

Thanks for the pointer. Actually RFC6052 just refers to RFC4291 from 2006 in this case. And that simply calls it an alternative representation.

Edit: RFC1884 from 1995 already had it, nothing has changed in that aspect.

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