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Category Archives for "Networking"

Public Videos: Routing Protocols

One of the delightful side effects of leaving the paid content business is that I no longer have to try to persuade anyone that my content is any good. That includes the “this video is now public” announcements – instead of elaborate introductions, I’ll just publish a short blog post with the links.

As of today, these videos (along with dozens of previously-released videos) from the Routing Protocols section of the How Networks Really Work webinar are no longer behind a login wall:

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Advertising IPs In EVPN Route Type 2

In my last post EVPN Deepdive Route Types 2 and 3, we took a deepdive into these two route types. I mentioned that the IP address of a host, a /32 or /128 address, could optionally be advertised. I also mentioned that this is mainly to facilitate features such as ARP suppression where a VTEP will be aware of the MAC/IP mapping and not have to flood BUM frames. However, in my last lab no IP addresses were advertised. Why is that? How do we get them advertised?

Currently, I have only setup a L2 VNI in the lab. This provides connectivity for the VLAN that my hosts are in, but it does not provide any L3 services. There is no SVI configured and there is also no L3 service configured that can route between different VNIs. The “standard” way of setting this up would be to configure anycast gateway on the leafs where every leaf that hosts the VNI has the same IP/MAC, but I consider this to be an optimization that I want to cover in a future posts. I prefer to break things down into their components and focus on the configuration needed for each component Continue reading

KU044: Making Kubernetes And Cloud-Native Workloads Environmentally Sustainable

Can clouds be green? Today we discuss sustainability in the tech industry, focusing on running Kubernetes and workloads in more efficient and environmentally friendly ways. Co-hosts Kristina Devochko and Michael Levan explore current tools, the reuse of resources like excess heat from data centers, and the challenges of sustainable energy infrastructure, such as electric cars... Read more »

Privacy Pass: Upgrading to the latest protocol version

Enabling anonymous access to the web with privacy-preserving cryptography

The challenge of telling humans and bots apart is almost as old as the web itself. From online ticket vendors to dating apps, to ecommerce and finance — there are many legitimate reasons why you'd want to know if it's a person or a machine knocking on the front door of your website.

Unfortunately, the tools for the web have traditionally been clunky and sometimes involved a bad user experience. None more so than the CAPTCHA — an irksome solution that humanity wastes a staggering amount of time on. A more subtle but intrusive approach is IP tracking, which uses IP addresses to identify and take action on suspicious traffic, but that too can come with unforeseen consequences.

And yet, the problem of distinguishing legitimate human requests from automated bots remains as vital as ever. This is why for years Cloudflare has invested in the Privacy Pass protocol — a novel approach to establishing a user’s identity by relying on cryptography, rather than crude puzzles — all while providing a streamlined, privacy-preserving, and often frictionless experience to end users.

Cloudflare began supporting Privacy Pass in 2017, with the release of browser Continue reading

Upcoming BGP Labs, 2024 Edition

It’s that time of the year when we create unreachable goals and make empty promises to ourselves (or others) that we subconsciously know we’ll fail.

I tried to make that process a bit more structured and create external storage for my lab ideas – I started publishing more details on future BGP lab scenarios. The lab descriptions contain a high-level overview of the challenge and the lab topology; the details will be filled in later.

Want to know what’s coming in 2024? Check out the Upcoming Labs page of the BGP Labs project.

Upcoming BGP Labs, 2024 Edition

It’s that time of the year when we create unreachable goals and make empty promises to ourselves (or others) that we subconsciously know we’ll fail.

I tried to make that process a bit more structured and create external storage for my lab ideas – I started publishing more details on future BGP lab scenarios. The lab descriptions contain a high-level overview of the challenge and the lab topology; the details will be filled in later.

Want to know what’s coming in 2024? Check out the Upcoming Labs page of the BGP Labs project.

A While, Career update and Ends with various Junos load commands.

It has been quite some time since my last blog post. The past few months have been busy, leaving little time to write. I am happy to share that I have started working as a site-reliability developer at Oracle. While it has only been a short while, I am enjoying the work.

Reflecting on the past year, I am happy to say it has been productive overall. I have had the opportunity to collaborate with various networking and software teams, which has taught me a lot about high-scale traffic patterns and migrations. Working in an operations role has been beneficial since it requires constant fire-fighting and documentation for improvements. This has made me more aware of traffic patterns and ways to improve reliability.

What can be improved?

However, I could benefit from more study on the software architecture and distributed system design parameters from a business perspective. I want to write more this year; the first half was better, but lacked in the second half, where most of the writing was private.

From a personal standpoint, 2024 needs more travel absolutely and some improvements in garden automation for summer 2024

Other updates

Finally, I have been working on some JNCIA-Devops Continue reading

About password security and credential stuffing

Common Falsehoods About Password Security and Credential Stuffing

TechCrunch published an article that gives class-action lawyers suing 23andMe a mouthpiece to editorialize about password security practices, masquerading as a news article. The upshot of the ~article~ editorial is this:

  1. A large number of 23andMe’s customers were subject to a credential stuffing attack.
  2. Design choices in 23andMe’s site allowed other customer data to be exposed via accounts compromised in the credential stuffing attack.
  3. 23andMe’s mitigations for credential stuffing attacks were inadequate.
  4. 23andMe should be held liable for this.

I want to focus here on the third point: credential stuffing attack mitigations. I’ve worked quite a bit on analyzing large credential stuffing attacks and recommending mitigations for them. I also served as a technical escalation point for customers who had a wide variety of strongly held false beliefs about password security credential stuffing mitigation. In reading various social media responses the 23andMe case, I see all these false beliefs turning up again. Let’s have a look at some.

False: Rate limiting login attempts is a great mitigation

The first question we need to answer here is: what do you mean by rate limiting? Usually there are two main rate limits that people Continue reading

Meshtastic quick setup

I wanted some nice offline mid range chat app, for when I don’t have data, or data roaming is too expensive. I also want it to work for people who are not amateur radio licensed, since my girlfriend stubbornly refuses to be interested in that.

Looks like the answer I’m looking for is Meshtastic, preferably with LoRalora]. I bought a couple of Heltec V3 ESP32 LoRa OLED and the matching case.

Maybe I’ll buy a battery, but I’m fine just powering it from a USB power bank.

The documentation makes a fair bit of assumptions about the user knowing the name for what they want, and what firmware provides what.

In short, what I think I want is to ignore the Heltec firmware, and instead just treat the Heltec V3 as the hardware that Meshtastic runs on.

The recommended way to flash, and for some cases even use, is the Meshtastic Web UI. It uses browser integration for serial ports and bluetooth. A nice idea, but it was extremely unreliable for me. The flasher worked for one device, but not the other. The chat client never worked at all.

Here’s what worked reliably for me:

  1. Download “stable” firmware Continue reading

BGP EVPN Part II: Network Virtualization Overlay with BGP EVPN and VXLAN – Introduction

In Figure 1-1, we have a routed 3-stage Clos Fabric, where all Inter-Switch links are routed point-to-point layer-3 connections. As explained in previous sections, a switched layer-2 network with an STP control plane allows only one active path per VLAN/Instance and VLAN-based traffic load sharing. Due to the Equal Cost Multi-Path (ECMP) supported by routing protocols, a routed Clos Fabric enables flow-based traffic load balancing using all links from the ingress leaf via the spine layer down to the egress leaf. The convergence time for routing protocols is faster and less disruptive than STP topology change. Besides, a routed Clos Fabric architecture allows horizontal bandwidth scaling. We can increase the overall bandwidth capacity between switches, by adding a new spine switch. Dynamic routing protocols allow standalone and virtualized devices lossless In-Service Software Update (ISSU) by advertising infinite metrics or withdrawing all advertised routes.

But how do we stretch layer-2 segments over layer-3 infrastructure in a Multipoint-to-Multipoint manner, allowing tenant isolation and routing between segments? The answer relies on the Network Virtualization Overlay (NVO3) framework. 

BGP EVPN, as an NVO3 control plane protocol, uses EVPN Route Types (RT) in update messages for identifying the type of advertised EVPN NLRIs (Network Continue reading

Public Cloud Networking Hands-On Exercises

I got this request from someone who just missed the opportunity to buy the ipSpace.net subscription (or so he claims) earlier today

I am inspired to learn AWS advanced networking concepts and came across your website and webinar resources. But I cannot access it.

That is not exactly true. I wrote more than 4000 blog posts in the past, and some of them dealt with public cloud networking. There are also the free videos, some of them addressing public cloud networking.

Read more …

Public Cloud Networking Hands-On Exercises

I got this request from someone who just missed the opportunity to buy the ipSpace.net subscription (or so he claims) earlier today

I am inspired to learn AWS advanced networking concepts and came across your website and webinar resources. But I cannot access it.

That is not exactly true. I wrote more than 4000 blog posts in the past, and some of them dealt with public cloud networking. There are also the free videos, some of them addressing public cloud networking.

Read more …

EVPN Deepdive Route Types 2 and 3

In my last post on Configuring EVPN, we setup EVPN but configured no services. In this post we will configure a basic L2 service so we can dive into the different EVPN route types. This post will cover route type 2 and 3 together as you will commonly see these together. This post will cover:

  • Discovery of VTEPs.
  • How to map a VLAN to a VNI.
  • Automatic generation of RD and RT.
  • Advertising MAC- and optionally IP address (route type 2).
  • Ingress replication with dynamic discovery of VTEPs (route type 3).

The topology we will use for this post is shown below:

Before diving into configuration, let’s discuss something that is often overlooked, VTEP discovery.

VTEP discovery

Without EVPN, VXLAN uses flood and learn behavior for discovery of VTEPs. This means that any host sending VXLAN frames would be considered a trusted VTEP in the network. This is obviously not great from a security perspective. When using EVPN, adding VTEPs is based on BGP messages. A VTEP will learn about other VTEPs based on these BGP updates. It’s not a specific route type, but rather any type of EVPN message. This makes it more difficult to add a rogue Continue reading

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