Cisco IOS - How to Configure VRF-Lite

What is VRF-Lite? VRF is a feature that allows you to create separate instances of the routing table. In turn allowing you to segregate and isolate different network types. When VRFs are used without MPLS it is classed as VRF-lite. VRF-lite configuration doesn’t need the route-target and can be…

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Cisco IOS - BGP Summarization

Introduction In order to reduce the amount of routing information within the routing table, routing summarization is used. Cisco IOS provides 3 types of BGP summarization: Aggregate Address - BGP is configured to advertise an aggregate network via the aggregate-address command. Manual - A summarized network is added to RIB…

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OpenStack Neutron - Port Security Explained

What is Port Security? By default Neutron enforces the following port security i.e. security on a per-port basis. Security Groups - All incoming and outgoing traffic is blocked for ports connected to virtual machine instances (unless a ‘Security Group’ has been applied).[1] Anti-Spoofing - As part of Neutron’…

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A Hands-on Guide to Netmiko and TextFSM

Introduction Within this article, we will look at two tools used in the world of network automation - Netmiko and TextFSM. Our examples will be based on a small topology consisting of 3 devices an Arista, a Cisco NXOS9K and a Cisco IOS router. Below shows the topology, Figure 1:…

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A Beginners Guide to Subnetting

Introduction Within this tutorial, we will provide a beginner’s guide to subnetting. Before we dive into subnetting we will look into the structure of an IP address, along with some of the key IP schemes that assist in modern day IP subnetting. Note: The scope of this document covers…

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Python - Threading vs Multiprocessing

Introduction In this article we will look at threading vs multiprocessing within Python, and when you should use one over the other. TL;DR What is the GIL (Global Interpreter Lock)? - Prevents more than 1 thread being run within a single CPython Interpreter/process. Why do we need the…

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