で、こういう感じで痕跡が残っている。
Dec 7 07:06:41 ******** sshd[*****]: Illegal user test from 152.14.53.40
Dec 7 07:06:44 ******** sshd[*****]: Failed password for illegal user test from 152.14.53.40 port ***** ssh2
Dec 7 07:06:46 ******** sshd[*****]: Illegal user guest from 152.14.53.40
Dec 7 07:06:48 ******** sshd[*****]: Failed password for illegal user guest from 152.14.53.40 port ***** ssh2
Dec 7 07:06:50 ******** sshd[*****]: Illegal user admin from 152.14.53.40
Dec 7 07:06:53 ******** sshd[*****]: Failed password for illegal user admin from 152.14.53.40 port ***** ssh2
Dec 7 07:06:55 ******** sshd[*****]: Illegal user admin from 152.14.53.40
Dec 7 07:06:57 ******** sshd[*****]: Failed password for illegal user admin from 152.14.53.40 port ***** ssh2
Dec 7 07:06:59 ******** sshd[*****]: Illegal user user from 152.14.53.40
Dec 7 07:07:02 ******** sshd[*****]: Failed password for illegal user user from 152.14.53.40 port ***** ssh2
Dec 7 07:07:06 ******** sshd[*****]: Failed password for root from 152.14.53.40 port ***** ssh2
Dec 7 07:07:11 ******** sshd[*****]: Failed password for root from 152.14.53.40 port ***** ssh2
Dec 7 07:07:15 ******** sshd[*****]: Failed password for root from 152.14.53.40 port ***** ssh2
Dec 7 07:07:17 ******** sshd[*****]: Illegal user test from 152.14.53.40
Dec 7 07:07:19 ******** sshd[*****]: Failed password for illegal user test from 152.14.53.40 port ***** ssh2