fir3net
March 21, 2017

What is SNI (Server Name Indication)?

in Concepts and Terminology
What is SNI? SNI (Server Name Indication) is an extension to the TLS protocol, that provides the ability to host multiple HTTPS-enabled sites on a single IP. How does it work? Prior to SNI the client (i.e browser) would send the requested hostname to the webserver within the HTTPS payload (Figure 1). Due to the hostheader being encrypted the SSL handshake and certificate retrieval had to be…

Route Leaking within an MPLS Network

in Cisco
Introduction First of all, what is a route leak? A route leak is the propagation of routing announcement(s) beyond their intended scope - RFC7908…

How to Configure an L3 MPLS VPN on Cisco IOS

in Cisco
Introduction Within this article we will walk through the various steps required in configuring MPLS. NOTE This article does not look to explain the…
cisco_cef

What is CEF (Cisco Express Forwarding)?

in Cisco
Introduction Cisco Express Forwarding (CEF) is a packet-switching technique used within Cisco routers. The main purpose of CEF is to optimize the…

How to Write Clean Code

in Programming
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…

Python - What are Context Managers?

in Python
What are Context Managers? Context managers are constructs that allow you to set something up and tear something down automatically, by using using…

Python - What are Static and Class Methods?

in Python
Have you ever seen some Python code and wondered what @staticmethod and @classmethod do ?In short, they are both methods that modify the default…

Python - What are Abstract Classes?

in Python
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…

Yum Error - Thread died in Berkeley DB library ... Error: rpmdb open failed)

in Linux
Issue When executing Yum you receive the following error, [root@william-gce blog]# yum install npm rpmdb: Thread/process 3934/139752225695488 failed:…

Python - What does Property() do ?

in Python
What is Property()? The purpose of this function is to create a property of a class. A property looks and acts like an ordinary attribute, except…

Cisco ASA - ICMP Inpsect and the Connection Table

in Cisco
Recently I've discovered that there is, well, fairly limited information online around this point. In this short article we will explain how ICMP…

The Pros and Cons to Azure's VNet Peering

in Cloud
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…

A Beginners Guide to AWS Identity and Access Management (IAM)

in Cloud
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…

A Beginners Guide to Application Services within AWS

in Cloud
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…

The Essential Guide To Moving Docker Containers

in Docker
Docker provides various commands/methods for moving containers. Within this article we will look at each of the commands, along with examples needed…