user@mypc:~$ sudo systemctl status ssh
● ssh.service - OpenBSD Secure Shell server
   Loaded: loaded (/lib/systemd/system/ssh.service; enabled; vendor preset: enabled)
   Active: active (running) since Sat 2019-01-19 15:10:47 CET; 1 day 8h ago
  Process: 16582 ExecStartPre=/usr/sbin/sshd -t (code=exited, status=0/SUCCESS)
 Main PID: 16585 (sshd)
    Tasks: 1
   Memory: 7.9M
      CPU: 1.677s
   CGroup: /system.slice/ssh.service
           └─16585 /usr/sbin/sshd -D

Jan 19 23:48:05 mypc sshd[31641]: Received disconnect from 159.65.228.248 port 56938:11: Normal Shutdown, Thank you for playing [preauth]
Jan 19 23:48:05 mypc sshd[31641]: Disconnected from 159.65.228.248 port 56938 [preauth]
Jan 19 23:48:06 mypc sshd[31643]: Invalid user dev from 159.65.228.248
Jan 19 23:48:06 mypc sshd[31643]: input_userauth_request: invalid user dev [preauth]
Jan 19 23:48:06 mypc sshd[31643]: Received disconnect from 159.65.228.248 port 57616:11: Normal Shutdown, Thank you for playing [preauth]
Jan 19 23:48:06 mypc sshd[31643]: Disconnected from 159.65.228.248 port 57616 [preauth]
Jan 19 23:48:07 mypc sshd[31645]: Invalid user dev from 159.65.228.248
Jan 19 23:48:07 mypc sshd[31645]: input_userauth_request: invalid user dev [preauth]
Jan 19 23:48:07 mypc sshd[31645]: Received disconnect from 159.65.228.248 port 58294:11: Normal Shutdown, Thank you for playing [preauth]
Jan 19 23:48:07 mypc sshd[31645]: Disconnected from 159.65.228.248 port 58294 [preauth]

user@mypc:~$ cat /var/log/auth.log | grep sshd
Jan 20 16:45:34 mypc sshd[26979]: Did not receive identification string from 185.253.157.108
Jan 20 19:09:42 mypc sshd[27809]: Did not receive identification string from 185.253.157.111