[cryptonector]

I don't understand yet where the "unreplayable" part comes from, but this isn't it.

[yencabulator]

Replayable: You observe attack against server A, you can take that attack and perform it against server B.

This attack is unreplayable because it cryptographically ties into the SSH host key of the server.

[cryptonector]

I know what replayable means. But even with your explanation of what makes it unreplayable it's not strictly true: you could replay the attack on the server it was originally played against.

[yencabulator]

Sure. But the interest is in being able to talk to server B to figure out if it's vulnerable; that's impossible, because the attack can't be replayed to it.

[cryptonector]

Thanks.