You now find yourself on a blog created by a CCNP R&S and Fortinet NSE7 networking nerd who write about topics I find interesting in the networking world.
My goal is to give the reader easily digestible explanations of various IT topics, new or old. As my interests cover Networking, Automation, Programming and more I hope to bring a variery of interesting articles for the IT-savvy reader.
Published 2026-09-25
I want to share how I implement graceful shutdown in my Go HTTP Servers. The goal of this article is to explain the graceful shutdown components and to help you implement it yourself. You only...
Published 2026-08-28
I'd like to share a BGP route filtering design I keep coming back to in my work as a network engineer. It's based on BGP communities, a tool that is widely used by Internet Service...
Published 2026-03-23
As part of migrating my blog from Python to Go, I wanted to gather anonymized statistics about which countries my visitors were coming from. This "small" feature ended up requiring a bit of optimization due...
Published 2026-03-14
2025 was the year I moved from Python to Go. I was developing an internal automation tool for work and Python was my language of choice. As it was reaching 10,000 lines of code I...
Published 2025-05-29
I have been teaching myself Golang over the last year or so. A big part of my learning has been through a peronal project I call Gollenet where I build a model of a "large"...
Published 2025-05-24
I recently led a workshop to help my network engineer colleagues get started with Ansible. It's written as a handholding start-from-zero guide that I shared as a git-repo on Github. The workshop contain eight chapters....
Published 2024-06-09
This article will cover three interesting problems I faced when deploying a Fortigate Firewall (FW) cluster in a VXLAN EVPN (MLAG) datacenter topology. The customer had requested that each FW member was to be deployed...
Published 2023-11-27
Over the years, I have seen more and more posts on the Internet from network engineers asking whether their new network design should use a firewall cluster that is Active-Passive (A-P) or Active-Active (A-A). My...
Published 2023-02-19
This article will be comparing MLAG and ESI for EVPN multihoming. Multihoming is the practice of connecting a device to multiple points in the network. For example, a server may connect to two switches for...
Published 2023-01-27
One of the strengths of VXLAN is that you can distribute the default gateway IP-address across multiple nodes for active-active forwarding. This is a massive leap forward when compared to active-passive HSRP and VRRP-based solutions...
Published 2023-01-13
This article will cover the main feature and selling point of VXLAN, tunneling Ethernet frames over a routed network to create L2VPN topologies. I will focus on Arista vEOS in my lab topology as it...
Published 2022-12-26
L3VPN may also be called IPVPN or Routed VPN. This post will focus on how VXLAN can be used to create routed VPN topologies, similar to the MPLS L3VPN technology which has been the industry-standard...
Published 2022-12-21
Virtual eXtensible LAN is a new and popular tunneling technology, allowing a network to tunnel Ethernet frames over a routed network. This solves many scalability problems, especially for large scale datacenter networks. The aim of...
Published 2022-10-31
OSPF Loop-Free Alternative (also called Fast-Reroute) is a technology for achieving fast failover times when a link goes down. Having the network drop or loop packets for 500-1000+ milliseconds while the routers compute a new...
Published 2022-09-27
Netconf is shaping up to become the next generation of network automation. It brings the promise of "network-wide" transactions, where any change is fully performed or not at all. The downside to Netconf is the...
Published 2022-08-05
IGMP Snooping is a switch feature that allows an Ethernet switch to participate in IGMP and use the information gathered to reduce unnecessary multicast flooding. If the switch doesn't participate, multicast traffic will be flooded...
Published 2022-07-26
I recently stumbled across a networking article mentioning an XOR operation performed by a host when deciding if packets to an IP-address should be sent to the default gateway or not. I wanted to learn...
Published 2022-02-06
Also known as Dijkstra's algorithm. I have been working with OSPF and IS-IS for a long time but never actually read any explanation of how the SPF algorithm actually gets the job done. This post...
Published 2022-01-10
A routed virtual private network. This is mostly sold by Service Providers, allowing customers to build a private WAN that interconnects their different sites. The main benefit for the customer is that they can use...
Published 2022-01-03
As opposed to PIM-DM, PIM-SM will only forward when explicitly requested to. Received IGMP Join messages on the LAN interface will trigger PIM join messages to be sent to upstream routers. But first we need...
Published 2022-01-02
A popular protocol that enables MPLS in your network. While OSPF and IS-IS advertise prefixes to the neighboring routers, LDP advertises labels for those prefixes allowing the packets to be MPLS encapsulated. LDP has two...
Published 2022-01-02
The MPLS protocol was developed in the 1990s to get the same functionality that ATM offered but over Ethernet. MPLS works by labeling IP packets. This label is then used to forward the packet instead...
Published 2021-12-26
This post assumes the reader has prior knowledge regarding MPLS L3VPN, LDP and PIM. We will be implementing this on JunOS and IOS-XR. This type of Multicast VPN used to be called *Next Generation MVPN*...
Published 2021-12-22
The simplest operating mode. A router will forward multicast traffic to its PIM neighbors unless it receives a Prune-message asking it to stop. If a Prune message is received then the interface the message was...
Published 2021-12-21
Multicast traffic flow from a single source to a group of receivers. This is different from IP Unicast that only has a single receiver. Multicast is also different from IP Broadcast which targets all devices...
Published 2021-12-19
Without any management protocol multicast will be forwarded exactly like broadcast. Any switch receiving a multicast frame will flood it on all other ports while a router will ignore them. Using IGMP, a multicast receiver...