Linux tutorials for systems administrators and users wanting to manage linux systems, covering various topics such as administration, security, performance tuning, upgrades, and maintenance.
By default Kernel-Based Virtual Machines(KVM) are not set up to access a serial console on the host using virsh. To enable a serial virsh console, so you can view text-based output on the host machine from the virtual machine you will need to make modifications to both the virtual machine and the physical machine. Enabling […]
What is SELinux? Security-Enhanced Linux (SELinux) was developed to provide access control for linux. It goes beyond file permissions and ACLs to create a more secure environment by limiting access. It is based on subjects, objects, and actions. A subject is the running command or application(example proftpd), the object is anything that can be accessed […]
What is FirewallD? Firewalld was introduced in CentOS 7/ RHEL 7 with both a GUI and command line interface for making changes. It is a alternative for using IPtables. If offers a zone based firewall configuration that allows you to enable different zones with different levels of trust. Different Zone possibilities Zones change be changed, […]
To recover the root password on a linux system if you do not have it have misplaced it depends on the major release of the OS. This guide will cover both CentOS 6(and prior releases) and CentOS 7. Recover a root password on CentOS 6 or older You will need to boot into single user mode. […]
Iptables is a firewall service included in CentOS, in CentOS 7 its offered as a alternative firewalld is offered as well. Iptables uses netfilter to filter chains. Essentially you create a chain of filter rules to process how incoming and outgoing data is handled. You can view more about iptables on Netfilter Iptables rule format […]
MariaDB is a fork of MySQL that was created from some of the original developers of mysql after MySQL was purchased by Oracle. Upgrading to MariaDB offers a range of benefits and is a relatively simple upgrade. It has more active development then MySQL currently and is just developed by Oracle support as MySQL is. […]
ModSecurity is an open source monitoring system for web applications. It has powerful rule sets that allow you to protect applications from attacks. View the project for more details. It provides a ton of features such as: More than 16,000 specific rules, broken out into the following attack categories: * SQL injection * Cross-site Scripting (XSS) […]