今日のattack to ssh

Feb 17 05:59:48 example sshd[60854]: Failed password for root from 221.12.158.45 port 49925 ssh2
Feb 17 10:45:19 example sshd[62874]: Failed password for invalid user author from 66.221.168.72 port 50313 ssh2
Feb 17 17:44:32 example sshd[66365]: Failed password for invalid user staff from 218.59.169.116 port 47428 ssh2
Feb 17 19:51:09 example sshd[67351]: Failed password for root from 69.53.126.238 port 1144 ssh2