Logwatch is a tool that analyzes and summarizes system logs, and can be used to monitor system activity on a central log server. Here are the basic steps for configuring Logwatch on a central log server: Install the Logwatch package on your central log server. On most Linux distributions, you can do this using the … Read more

Iptables is a firewall tool that is available on most Linux distributions, including CentOS and Red Hat. Here is a basic tutorial for configuring the iptables firewall on CentOS and Red Hat: Check the status of iptables by running the following command: sudo systemctl status iptables If the iptables service is not running, you can … Read more

Updating security patches in Linux using the command line interface (CLI) typically involves using the package manager specific to your distribution. Here are the general steps to update security patches in Linux using the CLI: Log in to your Linux system as the root user or as a user with sudo privileges. Open a terminal … Read more

To change the welcome login message in OpenSSH on Ubuntu Linux, you can follow these steps: Log in to your Ubuntu system as the root user or a user with sudo privileges. Open the sshd_config file using a text editor of your choice. This file is typically located in the /etc/ssh/ directory. For example, to … Read more

To change a user password on Red Hat Enterprise Linux (RHEL), you can use the passwd command as follows: Log in to the system as the root user or as a user with sudo privileges. Open a terminal window and type the following command to change the password for a specific user: passwd username Replace … Read more

In Linux or Unix, the sed command can be used to remove the ^M character (carriage return) from a file, which is often seen when files are transferred between Windows and Unix systems. Here’s an example sed command that removes the ^M character from a file: sed -i ‘s/\r//’ file.txt In this command, the -i … Read more

To read a file line by line in a Ksh (Korn shell) script on Unix, you can use a while loop with the read command. Here’s an example script that demonstrates how to read a file line by line in Ksh: #!/bin/ksh while read line do echo $line done < file.txt In this script, the … Read more

Views in BIND 9 are used to partition DNS information so that different DNS clients can see different sets of records. This can be useful in scenarios where you have both internal and external DNS clients that need to see different sets of records. To configure views in BIND 9 to partition external and internal … Read more

To configure mod_ssl for Apache on CentOS or RedHat, you can follow these steps: Install mod_ssl: First, you need to install mod_ssl if it is not already installed on your system. You can use the following command to install mod_ssl: yum install mod_ssl Generate SSL certificate and key: To use HTTPS for secure connections, you … Read more

The “Allowed Memory Size” error message in PHP indicates that the script has exhausted the memory limit allocated to it by the PHP configuration. The default memory limit for PHP scripts is 128MB, but this value can be increased or decreased depending on your server configuration. (www.ebsta.com) When you see an error message like “Allowed … Read more