On Fri, Jul 14, 2023 at 11:23 AM Walter H. via users <users@lists.fedoraproject.org> wrote:
Hello,

I've got a Win10 box und a Fedora  VM

both are latest updates / release [Win10 22H2 19045.3086 and Fedora 38]

I was used to connect to the Fedora VM from the Win10 box

- with the OpenSSH commands, that are nativly available in Windows
- with WinSCP
- or the ssh commands inside the WSL [Debian Distribution]

some time ago I noticed that the used keys from the WSL don't work any more;

I added this inside the Fedora in the sshd_config

HostKeyAlgorithms +ssh-rsa

PubkeyAcceptedKeyTypes ssh-rsa

then the login using the keys from WSL were working again;

but why didn't this help to login using the keys via the Win 10 OpenSSH
commands;

there I had to create new keys

ssh-keygen -t ed25519

and then to modify the above addings like this:

HostKeyAlgorithms +ssh-rsa,ssh-ed25519

PubkeyAcceptedKeyTypes ssh-rsa,ssh-ed25519

the same with WinSCP, there I had to gernerate a new key, too;

the used ssh-rsa keys are refused, even from WSL they work;

a bit confusing/strange;

See: <https://venafi.com/blog/best-practices-ssh-key-management-what-are-your-ssh-security-risks/>

More recent ssh versions will use defaults chosen for the current risk environment, so key types 
and other defaults change over time.  It would be unusual for WSL to be accessible from arbitrary 
internet sites, but that is in scope for Fedora, so you would expect Fedora defaults that increase 
security even if that is nor compatible with some other distributions running in WSL.