docs SSH config PubkeyAcceptedKeyTypes directive for Error: Permission denied (publickey)

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Creating a new section about adding the PubkeyAcceptedKeyTypes +ssh-ed25519 directive to the user's ~/.ssh/config file to fix the Error: Permission denied (publickey) issue, and this seems to affect macOS 12.3 with Git version 2.32.1.

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Aug 24 '22 18:08 srbdev

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Aug 24 '22 18:08 welcome[bot]

@srbdev Thanks so much for opening an issue! I'll triage this for the team to take a look :eyes:

Aug 25 '22 15:08 cmwilson21

Thanks for opening an issue! We've triaged this issue for technical review by a subject matter expert :eyes:

Oct 12 '22 21:10 github-actions[bot]

👋 hi there from the product manager for Git Systems at GitHub. I don't have a 12.3 machine handy to test this out, and my searching failed to turn up much that was related. @srbdev do you have any links handy which showcase this problem and/or solution? I'm not looking for a high burden of "proof" here, but I want to understand how common it is, which versions of macOS / Git it's likely to span, and so on. Thanks!

Oct 13 '22 15:10 vtbassmatt

I believe I adjusted the solution from this StackOverflow post: https://stackoverflow.com/a/35681481. Note that I have run into this same issue with trying to SSH to other systems from newer clients (Fedora 36 when it was first released and this new mac) whereas I could still SSH into these same systems from "older" clients (Debian, older macOS, etc.). This is what makes me think that is a client issue, and maybe not a server configuration issue. Hope that helps!

Oct 13 '22 17:10 srbdev

🙇 thank you for the pointer. I saw plenty of cases where macOS deprecated DSA keys, and those steps were the workaround. In that case, the instructions are to bring back something macOS had taken away.

What I couldn't find was any discussion of a recent-ish macOS having trouble using Ed25519 keys. Those are newer, and I can't figure out when macOS first shipped an SSH version capable of using them. And it seems odd (to me, anyhow) for any macOS release to support that key type but have it turned off by default.

Oct 13 '22 18:10 vtbassmatt