Possible break-in attempt?

[Grzegorz Junka]

On 21/07/2018 19:59, Miroslav Lachman wrote:
> Grzegorz Junka wrote on 2018/07/21 21:29:
>
> [...]
>
>>>>> There is no point to this foolishly alarming message. Be mindful 
>>>>> of the OTHER ways you must surely have in place to keep your sshd 
>>>>> hard against attack.
>>>>>
>>>> Good to know. But the documentation says setting to no prevents 
>>>> from using DNS in known_hosts. When I look into my known_hosts I 
>>>> see many dns-only names, e.g. github.com among others.
>>>>
>>>> GrzegorzJ
>>> In which man page or web page are you seeing this information?
>>
>>  > man sshd_config
>>
>>       UseDNS  Specifies whether sshd(8) should look up the remote 
>> host name,
>>               and to check that the resolved host name for the remote IP
>>               address maps back to the very same IP address.
>>
>>               If this option is set to “no”, then only addresses and 
>> not host
>>               names may be used in ~/.ssh/known_hosts from and 
>> sshd_config
>>               Match Host directives.  The default is “yes”.
>
> What version of FreeBSD do you have?
> On FreeBSD 10.4 there is
>
> UseDNS  Specifies whether sshd(8) should look up the remote host name,
>     and to check that the resolved host name for the remote IP
>     address maps back to the very same IP address.
>
>     If this option is set to “no”, then only addresses and not host
>     names may be used in ~/.ssh/authorized_keys from and sshd_config
>     Match Host directives.  The default is “yes”.
>
> And I don't think sshd_config should have any impact on client 
> configuration (known_hosts). It is controlled by ssh_config.

It's from 11.1-RELEASE-p1. I would hope that 11.1p1 is more correct than 
10.4?