Group administration

– Use the groupadd command to add a new group :

# groupadd [options] group_name – Use the groupmod command to modify an existing group :

# groupmod [options] group_name – Use groupdel to delete the group. You can remove a group even if there are users in the group. But you can […]

SELinux modes

SELinux gives that extra layer of security to the resources in the system. It provides the MAC (mandatory access control) as contrary to the DAC (Discretionary access control). Before we dive into setting the SELinux modes, let us see what are the different SELinux modes of operation and how do they work. SELinux […]

Introduction

– A packet filtering firewall reads incoming network packets and filters (allows or denies) each data packet based on the header information in the packet. The Linux kernel has built-in packet filtering functionality called Netfilter. – Two services are available in RHEL 7 to create, maintain, and display the rules stored by Netfilter: 1. […]

Question : How to disable firewalld and enable iptables instead?

Answer : To switch to from firewalld to iptables follow the steps given below.

1. Firstly ensure the iptables-services package is installed.

# yum install -y -q iptables-services 2. Then prepare the iptables rules you wish to use by editing /etc/sysconfig/iptables and /etc/sysconfig/ipt6tables.

3. Next, […]

Why should a Linux boot loader have password protection?

The following are the primary reasons for password protecting a Linux boot loader: 1. Preventing Access to Single User Mode – If an attacker can boot into single user mode, he becomes the root user. 2. Preventing Access to the GRUB Console – If the machine […]