We feature technical articles across the entire IT spectrum - CCNA networking, security, operating systems, cloud, and programming.

What is CEF (Cisco Express Forwarding)?


Introduction Cisco Express Forwarding (CEF) is a packet-switching technique used within Cisco routers. The main purpose of CEF is to optimize the forwarding of packets and increase the packet switching speed. History Prior to CEF there were 2 methods for packet-switching – Process- Switching and Fast-Switching. Process-Switching The first method, process-switching is the oldest and … Read more

How to Write Clean Code

Introduction Even bad code can function. But if code isn’t clean, it can bring a development organization to its knees. Every year, countless hours and significant resources are lost because of poorly written code[1]. Within this article we will take the key concepts, and points around writing Clean Code – referenced from the amazing book, The … Read more

Python – What are Context Managers?

What are Context Managers? Context managers are constructs that allow you to set something up and tear something down automatically, by using using the statement – with.  For example you may want to open a file, write to the file, and then close the file. Here is an example of a context manager, with open(path, … Read more

Python – What are Abstract Classes?

An abstract class can be considered a blueprint for other classes, allowing you to mandate a set of methods that must be created within any child classes built from your abstract class. Creation Lets first look at how you create an abstract class. First we import abc, we define the class as a metaclass using … Read more

Yum Error: Thread died in Berkeley DB library | rpmdb open failed

Issue When executing Yum you receive the following error, [[email protected] 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

Cisco ASA – ICMP Inspect and the Connection Table

Recently I’ve discovered that there is, well, fairly limited information online around this point. In this short article we will explain how ICMP inspect, whether disabled or enabled, affects the connection table. What is ICMP Inspect? “The ICMP inspection engine allows ICMP traffic to be inspected like TCP and UDP traffic. Without the ICMP inspection … Read more

The Pros and Cons to Azure’s VNet Peering

Introduction The other day I was asked to design a solution that required VNet peering, after some further digging and research into this feature I thought I’d share some of my findings with you all. Before we dive into the pros and cons, lets take a moment to quickly recap on what VNet peering actually … Read more

Beginners Guide to AWS Identity & Access Management (IAM)

AWS Identity and Access Management (IAM) is a web service that helps you securely control access to AWS resources for your users. You use IAM to control who can use your AWS resources (authentication) and what resources they can use and in what ways (authorization)[1]. Key features The key IAM features are, Provides centralized control … Read more

A Beginners Guide to Application Services within AWS

AWS provides a suite of application services, such as SQS, SNS, SES and SWF. Each service providing various features and rich toolsets to empower the development and design of your applications. SQS (Simple Queue Service) SQS is a web service that provides access to a distributed message queue. Messages are stored in the queue, these … Read more

The Essential Guide To Moving Docker Containers

Docker provides various commands/methods for moving containers. Within this article we will look at each of the commands, along with examples needed to move your Docker containers between your hosts and repositories. Repo to Repo Lets look at how we get an image from a repository and how we get our local image up to … Read more