Strange crypto choices

[Stuart Henderson]

On 2018-05-26, Christian Weisgerber <naddy at mips.inka.de> wrote:
> On 2018-05-26, Stuart Henderson <stu at spacehopper.org> wrote:
>
>> Changing HostKeyAlgorithms means that the existing entries in known_hosts
>> don't match, so the "WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED"
>> message is triggered.
>
> That's not true.  I'm using the default HostKeyAlgorithms along
> with a known_hosts file composed almost entirely of ssh-ed25519
> entries.
>
> The first entry in HostKeyAlgorithms is only used to pick the key
> type on first contact; afterwards ssh uses the key type from
> known_hosts as long as that type has an entry somewhere in
> HostKeyAlgorithms.
>
> As ssh_config(5) says under HostKeyAlgorithms:
>
>   If hostkeys are known for the destination host then this default
>   is modified to prefer their algorithms.
>

Ah - this *was* a problem (I remember it when ECDSA was added),
but I see it was fixed in 2010.