DCAUTO Exam Experience by Nick Russo

On 17 October 2023, I took and passed the Automating and Programming Cisco Data Center Solutions (DCAUTO) exam on my first attempt. This is the seventh DevNet exam I’ve passed. After the retirement of the Webex and IoT specialty exams, the Collaboration specialty and Expert exams remain the only two I haven’t attempted. Much like my experience with enterprise, service provider, and security automation, I have years of real-life experience automating various data center solutions, primarily by working with Nexus and NDO (formerly MSO). I’ve spoken about the topic on various podcasts and professional training courses many times. Believe it or not, I don’t have as much real-life automation experience with ACI or UCS, which are key data center products for Cisco, so I studied those areas intensely.

It’s worth mentioning that Cisco’s new certification road map introduces small changes at regular intervals to all of their certification exams. This is smart as it leads to less “blueprint shock” every few years, plus gives learners an opportunity to master the newest technologies in an incremental way. Because Cisco updated DCAUTO earlier this year, I took the v1.1 exam. I’m not kidding when I say the exam was Continue reading

Fibre Channel Addressing

Whenever we talk about LAN data-link-layer addressing, most engineers automatically switch to the “must be like Ethernet” mentality, assuming all data-link-layer LAN framing must somehow resemble Ethernet frames.

That makes no sense on point-to-point links. As explained in Early Data-Link Layer Addressing article, you don’t need layer-2 addresses on a point-to-point link between two layer-3 devices. Interestingly, there is one LAN technology (that I’m aware of) that got data link addressing right: Fibre Channel (FC).

Fibre Channel Addressing

Whenever we talk about LAN data-link-layer addressing, most engineers automatically switch to the “must be like Ethernet” mentality, assuming all data-link-layer LAN framing must somehow resemble Ethernet frames.

That makes no sense on point-to-point links. As explained in Early Data-Link Layer Addressing article, you don’t need layer-2 addresses on a point-to-point link between two layer-3 devices. Interestingly, there is one LAN technology (that I’m aware of) that got data link addressing right: Fibre Channel (FC).

Non-interactive SSH password authentication

SSH offers several forms of authentication, such as passwords and public keys. The latter are considered more secure. However, password authentication remains prevalent, particularly with network equipment.¹

A classic solution to avoid typing a password for each connection is sshpass, or its more correct variant passh. Here is a wrapper for Zsh, getting the password from pass, a simple password manager:²

pssh() {
  passh -p <(pass show network/ssh/password | head -1) ssh "$@"
}
compdef pssh=ssh

This approach is a bit brittle as it requires to parse the output of the ssh command to look for a password prompt. Moreover, if no password is required, the password manager is still invoked. Since OpenSSH 8.4, we can use SSH_ASKPASS and SSH_ASKPASS_REQUIRE instead:

ssh() {
  set -o localoptions -o localtraps
  local passname=network/ssh/password
  local helper=$(mktemp)
  trap "command rm -f $helper" EXIT INT
  > $helper <<EOF
#!$SHELL
pass show $passname | head -1
EOF
  chmod u+x $helper
  SSH_ASKPASS=$helper SSH_ASKPASS_REQUIRE=force command ssh "$@"
}

If the password is incorrect, we can display a prompt on the Continue reading

Worth Reading: Confusing Git Terminology

Julia Evans wrote another great article explaining confusing git terminology. Definitely worth reading if you want to move past simple recipes or reminiscing about old days.

Worth Reading: Confusing Git Terminology

Julia Evans wrote another great article explaining confusing git terminology. Definitely worth reading if you want to move past simple recipes or reminiscing about old days.

Post Mortem on Cloudflare Control Plane and Analytics Outage

Beginning on Thursday, November 2, 2023 at 11:43 UTC Cloudflare's control plane and analytics services experienced an outage. The control plane of Cloudflare consists primarily of the customer-facing interface for all of our services including our website and APIs. Our analytics services include logging and analytics reporting.

The incident lasted from November 2 at 11:44 UTC until November 4 at 04:25 UTC. We were able to restore most of our control plane at our disaster recovery facility as of November 2 at 17:57 UTC. Many customers would not have experienced issues with most of our products after the disaster recovery facility came online. However, other services took longer to restore and customers that used them may have seen issues until we fully resolved the incident. Our raw log services were unavailable for most customers for the duration of the incident.

Services have now been restored for all customers. Throughout the incident, Cloudflare's network and security services continued to work as expected. While there were periods where customers were unable to make changes to those services, traffic through our network was not impacted.

This post outlines the events that caused this incident, the architecture we had in place to prevent issues Continue reading

Can European Telcos Afford 5G and Broadband?

On the ‘net: Two on AI

I occasionally write over at Mind Matters on topics “other than technical.” Here are my two latest posts over there.

But what if you could steal something just as valuable as the contents of a lady’s handbag without anyone suspecting it and without impacting your user’s trust? What if you could take private information about millions of people, across the world, using that information to create what Shoshana Zuboff calls “behavioral surplus?” What if you could use that information to discover — and shape — people’s preferences without them even realizing it is happening? What if you could sell your user’s attention to the highest bidder?

While it seems evident that content created by a user prompt should not be copyrightable by the user, what about the designer and operator of the AI system? It might seem reasonable to infer the humans who create a system that, in turn, creates new “works” should be able to copyright those works.

On the ‘net: Model Based Thinking

Running a little late on cross posting stuff from Packet Pushers … but I suppose better late than never.

Model-based thinking can help engineers understand protocols and networks at a fundamental level. My previous post on network models focused on the Four Things model, an alternative to the OSI model for understanding network transport. I’ll continue with the Four Things, this time with a focus on routing.

Weekend Reads 110323

With security, the battle between good and evil is always a swinging pendulum. Traditionally, the shrewdness of the attack has depended on the skill of the attacker and the sophistication of the arsenal.

While cyberattacks on websites receive much attention, there are often unaddressed risks that can lead to businesses facing lawsuits and privacy violations even in the absence of hacking incidents.

A new login technique is becoming available in 2023: the passkey. The passkey promises to solve phishing and prevent password reuse.

Security researchers have discovered what they believe may be a government attempt to covertly wiretap an instant messaging service in Germany — an attempt that was blown because the potential intercepting authorities failed to reissue a TLS certificate.

Artists suing generative artificial intelligence art generators have hit a stumbling block in a first-of-its-kind lawsuit over the uncompensated and unauthorized use of billions of images downloaded from the internet to train AI systems, with a federal judge’s dismissal of most claims.

Professional artists and photographers annoyed at generative AI firms using their work to train their technology may soon have an effective way to respond that doesn’t involve going to the courts.

Intel is shedding its silicon photonics transceiver module business as part of restructuring and cost-cutting measures, offloading it to manufacturing company Jabil.

Domain Name System (DNS) abuse stands has proven a constant in the internet threat landscape, posing risk to the overall digital trust.

SpaceX is equipping its new satellites with inter-satellite laser links (ISLLs). They now have over 8,000 optical terminals in orbit (3 per satellite) and they communicate at up to 100 Gbps.

Calico monthly roundup: October 2023

Welcome to the Calico monthly roundup: October edition! From open source news to live events, we have exciting updates to share—let’s get into it!

Join us at KubeCon + CloudNativeCon North America 2023 We’re gearing up for KubeCon + CloudNativeCon 2023 in Chicago. Join us at booth #G13 for exciting Kubernetes security updates and pick up some cool new Calico swag! See what we’ve got planned.

Customer case study: eHealth Calico provides visibility and zero-trust security controls for eHealth on Amazon EKS. Read our new case study to find out how. Read case study.

Evaluating container firewalls for Kubernetes network security Learn why a traditional firewall architecture doesn’t work for modern cloud-native applications and results in a huge resource drain in a production environment. Read blog post

The State of Calico Open Source: Usage & Adoption Report 2023 Get insights into Calico’s adoption across container and Kubernetes environments, in terms of platforms, data planes, and policies. Read the report.

Open source news

• Read stories of Calico Open Source in action from our Calico Big Cats
  • Demystifying Calico Open Source: Empowering Your Network Security
  • Securing what others have overlooked with Calico
• Share your Calico Open Source journey and win Continue reading

HN708: The Future Of Networking With Brad Casemore – Part 1

HN708: The Future Of Networking With Brad Casemore – Part 1

The Future of Networking series continues with Brad Casemore, who survived multiple decades in the technology sector, including sixteen years as an analyst for IDC. He's been a longtime observer of networking markets, technologies, and trends. We talk about the interest in AI and try to separate the hype from the reality, multi-cloud networking, and more.

The post HN708: The Future Of Networking With Brad Casemore – Part 1 appeared first on Packet Pushers.

How IIoT Networks Use SD-WAN: Navigating the Right Path for Sensors

Enhancing Kubernetes Networking with the Gateway API

Kubernetes, the stalwart of container orchestration, has ushered in a new era of application deployment and management. But as the Kubernetes ecosystem evolves, networking  within these clusters has posed persistent challenges. Enter the Gateway API, a transformative solution poised to redefine Kubernetes networking as we know it. At its core, the Gateway API represents a paradigm shift in Kubernetes networking. It offers a standardized approach to configuring and managing network routing, traffic shaping, and security policies within Kubernetes clusters. This standardization brings with it a host of compelling advantages. Firstly, it simplifies the intricate world of networking. By providing a declarative and consistent method to define routing rules, it liberates developers and operators from the complexities of network intricacies. This shift allows them to channel their energies toward refining application logic. The Gateway API doesn’t stop there; it brings scalability to the forefront. Traditional Kubernetes networking solutions, like Ingress controllers, often falter under the weight of burgeoning workloads. In contrast, the Gateway API is engineered to gracefully handle high loads, promising superior performance for modern, dynamic applications. NGINX, now a part of F5, is the company behind the popular open source project, NGINX. NGINX offers a suite of technologies Continue reading

Video: Hacking BGP for Fun and Profit

At least some people learn from others’ mistakes: using the concepts proven by some well-publicized BGP leaks, malicious actors quickly figured out how to hijack BGP prefixes for fun and profit.

Fortunately, those shenanigans wouldn’t spread as far today as they did in the past – according to RoVista, most of the largest networks block the prefixes Route Origin Validation (ROV) marks as invalid.

Notes:

• ROV cannot stop all the hijacks, but it can identify more-specific-prefixes hijacks (assuming the origin AS did their job right).
• You’ll find more Network Security Fallacies videos in the How Networks Really Work webinar.

Video: Hacking BGP for Fun and Profit

At least some people learn from others’ mistakes: using the concepts proven by some well-publicized BGP leaks, malicious actors quickly figured out how to hijack BGP prefixes for fun and profit.

Fortunately, those shenanigans wouldn’t spread as far today as they did in the past – according to RoVista, most of the largest networks block the prefixes Route Origin Validation (ROV) marks as invalid.

Notes:

• ROV cannot stop all the hijacks, but it can identify more-specific-prefixes hijacks (assuming the origin AS did their job right).
• You’ll find more Network Security Fallacies videos in the How Networks Really Work webinar.

Unlocking IT Success: Navigating Talent Shortages with Integrated Solutions

KU039: Prepping For KubeCon North America 2023