On Mon, 25 Jun 2018 22:19:11 +0200, Paul de Weerd wrote:
> As far as I can see, these are all caused by 'the internet' trying to
> log in: I've not had any problems with sshd misbehaving and when I log
> in no such warning is logged. It happened for 'Invalid user' (36x), 'Failed
> password' (8x), 'Connection closed' (1x) and 'fatal: Timeout before
> authentication' (1x) in the space of just over 2 days.
To trigger the warning you need to force a diffie-helman key exchange.
For example:
ssh -oKexAlgorithms=diffie-hellman-group-exchange-sha256 somehost
Older clients don't support non-dh key exchange which is why you
get those warnings from bots scanning your ssh.
- todd
