To install DenyHosts on a Red Hat or CentOS Linux system, you can use the yum package manager and the install subcommand.
First, make sure that the epel-release repository is enabled on your system. You can enable it by installing the epel-release package using the following command:
sudo yum install epel-release
Next, use the yum command to install DenyHosts:
sudo yum install denyhosts
This will install DenyHosts and all the necessary dependencies.
Once DenyHosts is installed, you can configure it by editing the /etc/denyhosts.conf file. For example, you can specify the locations of the log files that DenyHosts should monitor, the maximum number of failed login attempts allowed before a host is blocked, and other options.
To start the DenyHosts service and enable it to start at boot, use the following commands:
sudo systemctl start denyhosts sudo systemctl enable denyhosts
This will start DenyHosts and configure it to monitor the specified log files for failed login attempts. If a host exceeds the maximum number of allowed failed login attempts, it will be blocked and added to the /etc/hosts.deny file.
It's always a good idea to carefully review the documentation and use the appropriate commands to install and configure DenyHosts on your system. This will help ensure that you have a secure and reliable way to block SSH attacks and prevent unauthorized access to your system.