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Category Archives for "Networking"

Routed Packet Walk in VXLAN/EVPN Network

In a previous post, I walked through how a packet gets bridged in a VXLAN/EVPN network. In this post, I’ll go through how a packet gets routed, that is, packet from one VNI to another VNI. The following topology will be used:

The lab has the following characteristics:

  • OSPF in the underlay.
  • Ingress replication for BUM traffic through the use of EVPN.
  • ARP suppression is enabled.

Server-2 initiates a ping towards Server-4:

Frame 562: 98 bytes on wire (784 bits), 98 bytes captured (784 bits) on interface ens257, id 4
Ethernet II, Src: 00:50:56:ad:f4:8d, Dst: 00:01:00:01:00:01
Internet Protocol Version 4, Src: 10.0.0.22, Dst: 198.51.100.44
Internet Control Message Protocol
    Type: 8 (Echo (ping) request)
    Code: 0
    Checksum: 0xd745 [correct]
    [Checksum Status: Good]
    Identifier (BE): 17 (0x0011)
    Identifier (LE): 4352 (0x1100)
    Sequence Number (BE): 1 (0x0001)
    Sequence Number (LE): 256 (0x0100)
    [Response frame: 563]
    Timestamp from icmp data: Mar  3, 2024 08:38:35.804470000 Romance Standard Time
    [Timestamp from icmp data (relative): 0.000701509 seconds]
    Data (40 bytes)

The destination MAC is 0001.0001.0001 which is the Anycast GW MAC configured on Leaf-2. As this MAC is used on SVI for VLAN 20 of Leaf-2, the Continue reading

Opinion: Digital Sovereignty and Internet Standards

There is a view that Internet standards, and the IETF in particular, are at the centre of many corporate and national strategies to exert broad influence and shape the internet to match their own preferred image. This view asserts that standards have become the most important component of the Internet’s infrastructure. Due to their economic and strategic importance, the process of creation of internet standards are inevitably subject to the intense economic and political tensions between diverse world views. There are, naturally, other views, along the lines that the IETF does little other than reflect the more general pressures and directions being taken by industry actors, and has no ability to exert any leadership role in this space.

Opinion: Digital Sovereignty and Internet Standards

There is a view that Internet standards, and the IETF in particular, are at the centre of many corporate and national strategies to exert broad influence and shape the internet to match their own preferred image. This view asserts that standards have become the most important component of the Internet’s infrastructure. Due to their economic and strategic importance, the process of creation of internet standards are inevitably subject to the intense economic and political tensions between diverse world views. There are, naturally, other views, along the lines that the IETF does little other than reflect the more general pressures and directions being taken by industry actors, and has no ability to exert any leadership role in this space.

Network Automation is not an Effortless Spacewalk

Recent events have shown us that successfully landing on the moon is anything but routine and no easy feat. Somehow it seems we are surprised. Thats puzzling. I recently read The Last Man on the Moon: Astronaut Eugene Cernan and America’s Race in Space by Eugene Cernan and Donald A. Davis * NASA Images Photo READ MORE

The post Network Automation is not an Effortless Spacewalk appeared first on The Gratuitous Arp.

Welcome to Security Week 2024

April 2024 will mark my one-year anniversary as the Chief Security Officer at Cloudflare. In the past year, we’ve seen a rapid increase in sophisticated threats and incidents globally. Boards and executives are applying significant pressure to security organizations to prevent security breaches while maintaining only slight increases to budgets. Adding regulatory scrutiny, global security leaders are under pressure to deliver on the expectations from executives to protect their company. While this has been the expectation for over 20 years, we have recently seen a significant rise in attacks, including the largest and most sophisticated DDoS attacks, and the continued supply chain incidents from Solarwinds to Okta. Along with more nation state sponsored attackers, it is clear security professionals – including Cloudflare – can’t let their guards down and become complacent when it comes to security.

This past year, I met with over a hundred customers at events like our Cloudflare Connect conference in London, Chicago, Sydney, and NYC. I spoke with executives, policy experts, and world leaders at Davos. And I've been in constant dialogue with security peers across tech and beyond. There is much consistency amongst all security leaders on the pain points and concerns of Chief Continue reading

Weekend Reads 040124


Exclusive Dell’s “return to office” mandate has left employees confused about which offices they can use and the future of their jobs – and concerned the initiative is a stealth layoff program that will disproportionately harm women at the IT giant.


FDC Pat Gelsinger wants to make Intel the world’s second largest chip manufacturer by 2030, and that means serving businesses the x86 giant has traditionally seen as competitors.


Intel revealed a new road map at its Intel Foundry Services (IFS) Direct event that will take the company into 2027. Itﾒs an extension of the road map Intel laid out nearly three years ago, shortly after Intelﾒs CEO Pat Gelsinger took the reins of the company.


It is not known who pilfered the information nor their motives, but this leak provides a first-of-its-kind look at the internal operations of a state-affiliated hacking contractor.


Apple has announced a new post-quantum cryptographic protocol called PQ3 that it said will be integrated into iMessage to secure the messaging platform against future attacks arising from the threat of a practical quantum computer.


Juniper Networks, currently in the process of being acquired by HPE, has been accused of violating US securities laws in a shareholder Continue reading

Hedge 215: Old Engineering Quotes

Reading people from the past can sometimes show us where today’s blind spots are–but sometimes we can just find the blind spots of the people who lived then. In this episode of the Hedge, Tom, Eyvonne, and Russ finish going through a selection of quotes from an engineering book published in 1911. This time, we find there are some things to agree with, but also some to disagree with.

EVPN – Asymmetric vs Symmetric IRB

It is well known that VXLAN supports bridging frames, that is, forwarding frames that belong to the same L2 segment. In the beginning, this is all that was supported. There was no VXLAN routing. In essence, the HW didn’t support taking a VXLAN encapsulated packet, decapsulating it, and then performing a L3 lookup. This meant that another device was needed to do the L3 lookup. Think of it as router on a stick where the VTEP would decapsulate the packet and forward it (based on L2 lookup) to a gateway. This gateway needed to have L3 interfaces for all the L2 VNIs that needed routing. Now, this is still applicable in a design where a FW should inspect traffic between all VNIs, but HW has supported for a long time to do VXLAN routing, that is, taking packet from one VNI and routing it to another VNI. This is referred to as Integrated Routing and Bridging (IRB), as the device is capable of both bridging and routing packets. IRB is described in RFC 9135.

There are two types of IRB, asymmetric and symmetric. Asymmetric vs symmetric refers to how the lookup is performed to do routing. Let’s first take a Continue reading

Lateral Security for the Private Cloud – Leveraging the Power of Seamless Integration

Because modern threats are distributed and multi-varied, protecting against them cannot be accomplished through a series of point security solutions.

Recently, there are discussions happening in the industry around the “platformization of security”. These are not new thoughts but are all essentially derived from how to offer a simpler solution to a complex problem. In my previous blog “Tackling the 5Cs of enterprise security with the advent of AI” , I had highlighted the preference for “consolidation” through a platform approach.

Since the security attack surface is ever broadening, customers prefer a holistic and integrated approach to solving it, versus a variety of point solutions each with independent bells and whistles. Integration in this context means seamless interworking between the different components, deep visibility across the components and providing customers with a secure plug-n-play experience that drives operational simplicity and ease of use. Fundamentally, his is the promise of the security platform.

 

Let’s consider this in the context of the private cloud, taking the industry-leading private cloud solution from VMware as an example. Enterprises choose private clouds because it gives them greater control, compliance, and, in many cases a significantly lower operating cost structure.

Customers adopting the Continue reading

Ansible Subelements Lookup Example

Ansible Subelements Lookup Example

When you're working with Ansible, you often come across situations where you need to deal with lists inside of lists. Imagine you have a bunch of servers, and each server has its own set of services to manage.

The subelements lookup plugin is designed to iterate over a list of dictionaries and a specified sub-list within each dictionary. Instead of writing complicated code to dig into each layer, subelements lets you glide through the outer list and then dive into the inner list easily.

What we will cover?

  • Subelements syntax
  • Subelements example
  • What are item.0 and item.1?
  • Subelements example with NetBox

Subelements Syntax

To use subelements in your playbook, you write a loop that tells Ansible what main list to look at and which sublist to go through. Here’s what a simple line of code looks like. 

loop: "{{ query('subelements', your_main_list, 'your_sublist_key') }}"

your_main_list is where you have all your main items (like servers), and your_sublist_key is the name of the sublist inside each main item (like tasks for each server). Ansible will then loop through each main item and its sub-items in turn.

Ansible Subelements Example

Suppose you have the following data structure defined in your playbook.

 Continue reading

Electrics and plumbing

Unless you plan to live by candle light and bathe in the canal you are going to need electrics and hot water. The two main players when it comes to boat electrics are Victron and Mastervolt, I went for victron as their whole eco-system seems a lot more advanced and customisable (are a lot more guides, examples and advise readily available online). In terms of hot water and heating a calorifier is the only real sensible option, for the diesel heater I chose Webasto over Eberspacher as I liked how they how they have incorporated the use of Heatmiser thermostat controllers.

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