I've added 2 step authentication and it's working perfectly fine. However, I still get the LFD failures. For example:
Time: Tue Apr 11 18:46:34 2017 +0100
IP: 81.199.16.113 (UG/Uganda/81.199.16.113.satcom-systems.net)
Failures: 5 (sshd)
Interval: 3600 seconds
Blocked: Permanent Block
Log entries:
Apr 11 18:46:23 serv sshd[23741]: Invalid user admin from 81.199.16.113
Apr 11 18:46:23 serv sshd[23741]: pam_unix(sshd:auth): authentication failure; logname= uid=0 euid=0 tty=ssh ruser= rhost=81.199.16.113
Apr 11 18:46:25 serv sshd[23741]: Failed password for invalid user admin from 81.199.16.113 port 3561 ssh2
Apr 11 18:46:28 serv sshd[23741]: Failed password for invalid user admin from 81.199.16.113 port 3561 ssh2
Apr 11 18:46:30 serv sshd[23741]: Failed password for invalid user admin from 81.199.16.113 port 3561 ssh2