Clay Curtis

Exploring Link Aggregation Hashing Algorithms in Python

Last week I was stuck in the never ending death scroll on Twitter, and actually came across something pretty interesting. It was a post on Twitter from Christopher Hart deep diving into Equal-Cost Multi-Pathing (ECMP). In this thread he gets into the details of how a switch determines which link

network automation

RUN DFZ - Bringing the Internet to a Lab Near You

One of the things I have wanted to test over the years was having realistic Internet BGP data inside of a lab network. Traditionally this would entail peering with a real router in production. I have never been in an environment that would be OK with this, so I always

network automation

Network Automation Text Parsing Landscape

Whether you like it or not, the networking industry is stuck with (and will be for many years to come), vendors and devices with no API, inconsistent interfaces, differing configuration and runtime CLI formats. This means that as much as you hate screen-scraping and regex, it's here to stay. In

network automation

The New CCIE Capture the Flag Competition @ Cisco Live

At Cisco Live this year in Las Vegas, a coworker (Paul Giblin Twitter: @dreamlessod) and I decided to attended a new kind of event hosted by Cisco. The event was titled "Cisco Capture the Flag: A Full-Stack, Team-Based Competition". The competition was a structured game where teams compete

networking

Reclaiming Public IP Addresses Using Server Name Indication

Have you have ever been in a situation where you have been given a block of addresses by your Internet provider and you have exhausted that space by publishing services to the Internet? Yea, me too and it sucks. The typical solution would be to get a larger block from

network automation

Line-Rate Flow Capture to ELK Stack

Introduction In certain environments it is necessary to get flow data from different places in your network for compliance or security in general. Recently I ran across a situation in which the native flow gerenators within the Cisco Nexus platform were only able to do 1 in 1000 sampling due

network automation

ELK Stack for Network Operations [RELOADED]

Update This is an update to my original article about ELK for Network Operations. This is built on the latest version of ELK (Elasticsearch 1.5, Logstash 1.5.0.rc2, and Kibana 4) on Centos 7. What Is The ELK Stack? ELK stack is a powerful set of tools

network automation

FOSS Solution For Network Configuration Backups

In the networks that I run I typically try and follow the FCAPS model. The (C)onfiguration part of that is often overlooked. I have used paid and free products, and they all work fine, but I wanted something that was simple, version controlled, and fully open source. This solution

security

The Hitchhiker's Guide to Using OpenSSL for Managing Certificates

Introduction Over the years I have had to do a lot of repetitive tasks in OpenSSL, and I've always had to hunt down what command I needed to use. So, I finally made a list of the most common use cases and commands, and now it's time to share. A

network automation

ELK For Network Operations

UPDATE Check out the latest version of this guide here. The updated article utilizes the latest version of the ELK stack on Centos 7. What is ELK? ELK is a powerful set of tools being used for log correlation and real-time analytics. This post will discuss the benefits of using