Invalid Logons last night from 62.75.162.91

My terse  response below

lock down ssh access if required

better yet , define a ssh port other  22 ( I use 2022 or 2222 )

e.g http://socpuppet.blogspot.com/2014/12/hardening-your-unix-ssh-server-access.html

block cbc base ciphers if you can

use  MFA for admin access &  if you can't lock it down and must allow ssh open

delete any references to "admin"  and create  system accounts that has NO admin in the name or root

or force  user to use ipsec/sslvpn into the  appliance  and then ssh once secured thru that tunnel to maybe a local-loopback

e.g here's one approach YMMV

http://socpuppet.blogspot.com/2015/03/sslvpn-sslroot-management-access.html

Now go drink a  wheat beer and don't worry about it ;)

Seriously,  brute-force attacks or  ssh-login is nothing new. And as long as you have tcp.port22 open to the world, you will always seen failed logins. Why all your  devices at at the same time, tells me it a admin of your network or somebody that was testing something and knows your addresses.

Can you copy paste the syslog message?