sshguard: Protection for OpenSSH
Are you concerned about brute force dictionary attacks on SSH? Given the popularity of these attacks, you should be. sshguard is a new tool to help protect against such attacks. Although it is still in beta stage, it appears to work well.
OpenSSH provides a secure alternative to clear-text logins used by first-generation network protocols like Telnet and FTP. But it's not enough simply to use SSH instead of Telnet -- you have to use it wisely. If you use weak passwords with SSH, a brute force dictionary attack will reveal your secrets as easily as if your password were sent in clear text.
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