Rahul Sahu The “bad username” error message when reading the “/etc/cron.d” file on Linux typically occurs when the username specified in the cron job does not exist on the system. To resolve this issue, you can either: Correct the username in the cron job file: # nano /etc/cron.d/your_cron_job_file Use a valid username that exists on your system. … Read more
To configure Postfix to use an external SMTP server as a relayhost (smarthost), you can use the following steps: Edit the Postfix configuration file: # nano /etc/postfix/main.cf Add or modify the following line: relayhost = smtp.example.com:587 Replace smtp.example.com with the hostname or IP address of your SMTP server and 587 with the port number if … Read more
To install KVM on a headless Ubuntu 16.04 LTS server, you can use the following steps: Verify that your system supports virtualization: # egrep -c ‘(vmx|svm)’ /proc/cpuinfo If the output is 0, your system does not support virtualization. Install the necessary packages: # apt-get update # apt-get install qemu-kvm libvirt-bin bridge-utils Add your user to … Read more
To force users to use secure passwords on Ubuntu or Debian Linux, you can use the “pam_cracklib.so” module in PAM (Pluggable Authentication Modules). This module checks the strength of passwords before allowing them to be set. Here are the steps to enable password checks with PAM: Install the “libpam-cracklib” package: # apt-get install libpam-cracklib Edit … Read more
To apply patches on an OpenBSD system, you can use the “syspatch” command. This command updates the operating system and packages with the latest security patches. To use it, run the following command as root: # syspatch If there are no patches available, you will see the message “Your system is up to date.” If … Read more
To apply patches on an OpenBSD system, you can use the “syspatch” command. This command updates the operating system and packages with the latest security patches. To use it, run the following command as root: # syspatch If there are no patches available, you will see the message “Your system is up to date.” If … Read more
You can create an empty file in Linux using the touch command or by using a text editor. Here’s the general process for creating an empty file in Linux: Using touch: You can create an empty file using the touch command and specify the name of the file as an argument: touch [file-name] For example, … Read more
You can create a snapshot of a KVM virtual machine (VM) or domain in Linux using the virsh command-line tool. Here’s the general process for creating a snapshot in a KVM virtual machine or domain: Connect to the KVM host: Connect to the KVM host using ssh or by using the console directly. List running … Read more
To live patch the Ubuntu Linux Kernel without rebooting the server, you can use a tool called “Kpatch”. Kpatch is a dynamic live-patching system that allows you to apply kernel patches without the need for a reboot. It works by patching individual functions in the running kernel, rather than applying a full patch to the … Read more
To patch and protect the Linux kernel Zero Day Local Privilege Escalation Vulnerability (CVE-2016-5195) from Oct 21, 2016, follow these steps: Check your kernel version: uname -r Update your system: sudo apt-get update && sudo apt-get upgrade Install the latest security patches: sudo apt-get dist-upgrade Reboot your system: sudo reboot Note: The above steps are … Read more