Operating Systems

Introduction Within this article, we will configure a BIND server within Ubuntu. The advantages of having a local DNS server include: Reduced latency to DNS requests/responses Ability to add private addresses and full flexibility of zone names. Especially useful for VMware installations. It is important to note that the steps provided, are based on a quick setup. Due … Read more

Introduction Most likey there will be a time (for one reason or another) where you need to insert a number of spaces to a set of lines within a text file.Within this short article we will show you how via the use of VIM. Steps 1. Within VIM select blockwise visual mode, by pressing CTRL-V.2. … Read more

Introduction Within the Linux kernel, knowing how memory is separated is extremely important. As knowing what programs reside where, and the requirement on the system to move memory from one place to another, can provide a huge insight into the performance, or lack of, within a system. And when it comes to the world of … Read more

Definition MacVTap is a Linux device driver, based upon the combination of – Macvlan and TAP (descriptions below), that allows for the creation of virtual (tap-like) interfaces. Each virtual network interface is assigned its own MAC and IP address, then attached to the physical interface (also know as the lower interface), Macvlan – Linux kernel … Read more

Abstract The scope of this article is to describe, at a high level, the journey a frame takes through a Linux based system. NOTE This article does not cover Linux kernel performance issues and caveats, for more information around this please see pushing the limits of kernel networking. Ingress Lets first look at the path … Read more

The other day I asked myself, What is the difference between apt-get update and apt-get upgrade? As I’m sure many other people, at some point may ask the same, I thought I would share the answer. Quite simply, apt-get update – updates the list of available packages, and their versions. However it does NOT upgrade … Read more

Issue When executing Yum you receive the following error, [root@william-gce blog]# yum install npm rpmdb: Thread/process 3934/139752225695488 failed: Thread died in Berkeley DB library error: db3 error(-30974) from dbenv->failchk: DB_RUNRECOVERY: Fatal error, run database recovery error: cannot open Packages index using db3 – (-30974) error: cannot open Packages database in /var/lib/rpm CRITICAL:yum.main: Error: rpmdb open … Read more

What is Git? Git is a version control system that is used for software development and other version control tasks. As a distributed revision control system it is aimed at speed, data integrity, and support for distributed, non-linear workflows[1]. Create Repository To create a new repository, the command git init is used, within your directory. … Read more

Git provides 3 types of merging, Fast-Forward, Automatic and Manual. A manual merge is required when git is unable to resolve any conflicts , this results in a merge conflict. Within this example we will generate a merge conflict and then manually resolve from within the command line. File First, lets look at the contents … Read more

Git provides various global configuration options for colorizing the output.[1] In order to enable these options, run the following commands. This will, in turn update your ~/.gitconfig file. git config –global color.ui alwaysgit config –global color.branch alwaysgit config –global color.diff alwaysgit config –global color.interactive alwaysgit config –global color.status alwaysgit config –global color.grep alwaysgit config –global … Read more

In order to make your life easier when working with git, this article provides the steps to display the current local git branch within your bash prompt. This not only saves you time, but also prevents the potential for human error by ensuring you are not making changes to the wrong branch. Download Script First … Read more

Introduction The Uncomplicated Firewall (ufw) is a frontend for iptables and is particularly well-suited for host-based firewalls. ufw provides a framework for managing netfilter, as well as a command-line interface for manipulating the firewall. ufw aims to provide an easy to use interface for people unfamiliar with firewall concepts, while at the same time simplifies … Read more