SSH server can be configured to allow an authenticating client a number of tries for a set period of time before the authentication is considered a failure. By default an SSH user is allowed 3 attempts within 120 seconds (2 minutes) to authenticate whereby the client will then be given the Permission denied error and the session closed.
The failed login will be logged and the user will then be allowed to log in again. This might slow down a malicious login attempts but will not deter brute-force attacks.
$ sudo vi /etc/ssh/sshd_config [sudo] password for user:
LoginGraceTime 60
Remove # if exist at the start of the line to uncomment.
Can also use unit such as m for minute. Set the value to 0 to disable the feature.
LoginGraceTime 1m
MaxAuthTries 5
Remove # if exist at the start of the line to uncomment.
$ sudo systemctl restart sshd
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