Bloqueando força bruta ssh

Salve Pessoal!

Assim que instalei o servidor Zimbra no Ubuntu Server 7.04, em um VPS da DigitalOcean, com IP público setado na placa de rede ( eht0), e percebi que estava recebendo nos arquivos de log, tentativas de invasão por força bruta, veja as entradas dos logs:

Feb 24 16:01:30 mx sshd[17986]: input_userauth_request: invalid user rails [preauth]
Feb 24 16:01:32 mx sshd[17986]: Failed password for invalid user rails from 78.47.131.180 port 54602 ssh2
Feb 24 16:01:32 mx sshd[17986]: Received disconnect from 78.47.131.180 port 54602:11: Normal Shutdown, Thank you for playing [preauth]
Feb 24 16:01:32 mx sshd[17986]: Disconnected from 78.47.131.180 port 54602 [preauth]

Feb 24 16:00:13 mx sshd[17596]: Invalid user rails from 78.47.131.180
Feb 24 16:00:13 mx sshd[17596]: input_userauth_request: invalid user rails [preauth]
Feb 24 16:00:15 mx sshd[17598]: Invalid user user from 138.201.144.247
Feb 24 16:00:15 mx sshd[17598]: input_userauth_request: invalid user user [preauth]
Feb 24 16:00:15 mx sshd[17596]: Failed password for invalid user rails from 78.47.131.180 port 35440 ssh2
Feb 24 16:00:15 mx sshd[17596]: Received disconnect from 78.47.131.180 port 35440:11: Normal Shutdown, Thank you for playing [preauth]
Feb 24 16:00:15 mx sshd[17596]: Disconnected from 78.47.131.180 port 35440 [preauth]

Feb 24 16:02:55 mx sshd[18792]: Failed password for invalid user ubuntu from 138.201.144.247 port 34522 ssh2
Feb 24 16:02:56 mx sshd[18792]: Received disconnect from 138.201.144.247 port 34522:11: Normal Shutdown, Thank you for playing [preauth]
Feb 24 16:02:56 mx sshd[18792]: Disconnected from 138.201.144.247 port 34522 [preauth]

Como o servidor está publicado na web, instalei o programa fail2ban que e parou os ataques, pois ele bloqueia as múltiplas tentativas de falha de login ssh.

Até mais!