the worlds gone mad

Pynetbox API calls using variables

using variables for netbox api urls and filters

Recently whilst using pynetbox to create NetBox environment objects I had a need to use variables in the URL of the API calls to allow for reusable functions to perform API calls based on the URL and data fed in as arguments. The reason the URL needs to be fed in as an argument when calling the function is because each NetBox element uses a different API URL.

SD-WAN service-side MPLS VPN

using bgp mpls vpn for service-side cisco sd-wan connections

This post goes through how to configure MPLS VPN on the service-side of a Cisco SD-WAN edge device, so the south-side towards non-SD-WAN devices. What I am trying to achieve is to advertise the differing SD-WAN VPN (VRF, why Cisco have to call these VPNs beats me) prefixes to a core switch (using a ASR in the lab) directly connected to the SD-WAN router. This could be accomplished using per-VRF interfaces (or sub-interfaces) and BGP peerings, but a neater solution is to pass all the routing information over one the BGP MPLS VPNv4 peering.

F5 BIG-IP DNS Express

using big-ip dns express as a local dns server

As part of a POC I deployed a pair of HA F5 LTM/GTM at home to use for all things DNS based. It is an indulgent over the top DNS solution for a 1 bed flat, but hey-ho we are in a pandemic….. This guide does not go through the HA F5 or GTM (still cant stop calling it that) configuration, it is focussed around using ZoneRunner for DNS (bind) with these zones transferred into DNS express and serviced by a listener.

Nornir: Tasks, Plugins and Templates

building and running tasks

Nornir tasks are run against all or a subset of inventory members with the result formatted into a framework structured to show what was run against whom and the results. Tasks can be custom built python code or pre-built plugins that have been installed and imported.

Nornir: Inventory Structure and Filtering

updating and filtering the inventory

The inventory is at the core of Nornir holding all the hosts that tasks will be run against and the variables that will be used by those tasks. Before any tasks can be run by Nornir the inventory has to be initialised.

Nornir - The Basics

general nornir information to get started

If you have an understanding of Python and have been working with Ansible it is likely at some point you will get to the stage where you ask yourself ‘there has to be something better’. For network automation that better could well be Nornir.

Virtual Tunnel Interface (VTI) VPN

vti ipsec vpn between asa and asr

Over the years I have built numerous IPsec VPNs on ASAs using crypto maps and an ACL for the interesting traffic. For a simple solution to join small sites with no need for routing these work great and keep the complexity down to a minimum. For more complex environments or cloud connectivity you are probably going to need to use VTIs, this post goes through the process of building VTI VPNs between an ASR and ASA.