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Category Archives for "Networking"

Using the Linux cut command to grab portions of lines from files

One surprisingly easy command for grabbing a portion of every line in a text file on a Linux system is cut. It works something like awk in that it allows you to select only what you want to see from files, enabling you to pull fields (regardless of the delimiter used), characters or bytes. To check on cut, you can ask about its version like this:$ cut --version cut (GNU coreutils) 8.32 Copyright (C) 2020 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <https://gnu.org/licenses/gpl.html>. This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. Written by David M. Ihnat, David MacKenzie, and Jim Meyering. Selecting by field To illustrate how the cut command works, we'll first run commands using a sample "cities" file that contains details of the largest cities in the US in a tab-separated format. The lines in this file look something like what is shown below:To read this article in full, please click here

ZeroLB, a New Decentralized Pattern for Load Balancing

Marco Palladino Marco Palladino is an inventor, software developer and internet entrepreneur based in San Francisco. As the CTO and co-founder of Kong, he is Kong’s co-author, responsible for the design and delivery of the company’s products, while also providing technical thought leadership around APIs and microservices within both Kong and the external software community. Prior to Kong, Marco co-founded Mashape in 2010, which became the largest API marketplace and was acquired by RapidAPI in 2017. With advancements in technology-driven by the Kubernetes — new architectural patterns have emerged to provide decentralized load balancing, yet portable across various platforms and clouds. The old monolithic and centralized load balancer, a technology largely stuck in the early 2000s, becomes deprecated in this new distributed world. The most common breed of load balancers being deployed across every application — centralized load balancers — are a legacy technology. They don’t work well in our new distributed and decentralized world. Remnants of a monolithic legacy way of doing things that did not adapt to modern best practices, centralized load balancers prevent users and organizations from effectively transitioning to the cloud Continue reading

The Grass is Always Greener

This last week I was talking to someone at a small startup that intends to eliminate all the complex routing from campus networks. In the past, when reading blog posts about Kubernetes, I’ve read about how it was designed to eliminate routing protocols because “routing protocols are so complex.”

Color me skeptical.

There are two reasons for complexity in a design. The first is you’re solving a hard problem. The second is you’ve made bad design choices in the past, and you’re pasting complexity on top to solve some perceived problem (whether perceived or real).

The problem with all this talk about building something that’s “less complex” is people tend to see complexity of the first kind and think, “we can get rid of that complexity if we start over.” Failing to understand the past before building the future is a recipe for repeated failures of the same kind. Building a network without a distributed routing protocol hasn’t been tried before either, right? Well, yes, it has … We either forget how it turned out, or we say “well, that’s not the same thing I’m talking about here” (just like “real socialism hasn’t ever been tried”).

Even worse, Continue reading

Dynamic DNS Security Blues

Whenever you run into a network problem, the wise network admin or sysadmin always remembers “It’s always Black Hat USA 2021 security conference Ami Luttwak and head of research simple loophole that allowed them to intercept dynamic DNS (DDNS) traffic going through managed DNS providers like Amazon and Google. And, yes, that includes the DDNS you’re using on your cloud. And, if you think that’s bad, just wait until you see just how trivial this attack is. Our intrepid researchers found that “simply registering certain ‘special’ domains, specifically the name of the name server itself, has unexpected consequences on all other customers using the name server.

Network Break 345: Marvell Acquires High-End Ethernet ASICs; Arista CEO Says Component Shortage ‘Worst I’ve Seen’

This week's Network Break podcat discusses Marvell's Innovium buy and its impact on the high-end Ethernet market, new Juniper security software for applications, Arista financial results and component concerns, and more IT news.

The post Network Break 345: Marvell Acquires High-End Ethernet ASICs; Arista CEO Says Component Shortage ‘Worst I’ve Seen’ appeared first on Packet Pushers.

Tech Bytes: Pharma Distributor Ensures Uptime, App Performance With Aruba SD-WAN (Sponsored)

Today on the Tech Bytes sponsored podcast we're talking SD-WAN with Ascent Health & Wellness, a digital healthcare platform for pharmaceutical distribution. We discuss how the company deployed Aruba EdgeConnect to ensure uptime for critical pharmaceutical fulfillment services, speed up order processing, and provide robust performance for cloud-based business apps.

Tech Bytes: Pharma Distributor Ensures Uptime, App Performance With Aruba SD-WAN (Sponsored)

Today on the Tech Bytes sponsored podcast we're talking SD-WAN with Ascent Health & Wellness, a digital healthcare platform for pharmaceutical distribution. We discuss how the company deployed Aruba EdgeConnect to ensure uptime for critical pharmaceutical fulfillment services, speed up order processing, and provide robust performance for cloud-based business apps.

The post Tech Bytes: Pharma Distributor Ensures Uptime, App Performance With Aruba SD-WAN (Sponsored) appeared first on Packet Pushers.

Network certs 2021: Significant raises for the right ones

COVID-19 kicked off one of the most disruptive economic periods since World War II, and companies scrambled to shift business processes to the cloud to meet escalating digital demands. In fact, companies digitized many activities at a rate 20% to 25% faster than previously thought possible, according to research from McKinsey & Company.That acceleration has impacted the IT workforce: 85% of IT hiring managers say their hiring needs have changed, according to a survey by colocation provider INAP. This creates an opportunity for IT professionals who want to move ahead in their careers. Getting trained in key technologies can be a steppingstone not only to better pay but also to leadership jobs with more responsibilities.To read this article in full, please click here

Top Online Learning Websites

Online learning was on the rise for many years. However, the pandemic pushed this learning even further as people are now doing everything from their homes. After all, online is more effective, cheaper, and doesn’t require much time and effort than conventional education.

If you want to make use of this time to learn more, you are in the right place. Here are the top online learning websites for you to learn new skills.

1. Udemy

Udemy is one of the most popular online learning platforms out there. You can choose from more than a hundred thousand courses. That is why it is an ideal choice for people that want to diversify their education by learning new things.

Keep in mind that you will have to purchase a course and then start learning. However, courses are not too expensive and will not put a significant dent in your pocket. After each course, you get a completion certificate.

2. Skillshare

Skillshare is a highly diverse learning platform. It has more than twenty-thousand classes, and it offers a two-month free trial to all its users. After that, you can either pay $15 each month or $99 per year.

From lifestyle to music Continue reading

LISP – OMP – BGP EVPN Interoperability – Part VII: End-to-End Data-Plane Operation

 

Introduction

 

This chapter introduces Data-Plane operation and explains how the data packets from EP3 (IP 172.16.30.3) in Datacenter Fabric are forwarded via SD-WAN to EP1 (IP 172.16.100.10) in Campus Fabric. (1) EndPoint3 sends the ICMP Request packet to its gateway switch Leaf-11. Leaf-11 makes routing decisions based on the VRF NWKT routing table. Before forwarding the packet, Leaf-11 adds a VXLAN header where it uses L3VNI 10077. It also sets the outer IP header where it uses the Border-Leaf-13 tunnel interface’s IP address 192.168.50.13 as a destination. Spine-1 routes the packet to Border-Leaf-13 based on the outer IP address. Border-Leaf-13 notices that the destination IP address of the received IP packet belongs to its’s NVE1 tunnel interface. It removes the outer IP header and based UDP destination port it notices that this is VXLAN encapsulated packet. It knows that L3VNI 10077 belongs to VRF NWKT. It strips off the VXLAN header and routes the packet to vEdge-2. The ingress interface towards DC in vEdge-2 belongs to VPN 10. vEdge-2 consults its routing table. Based on it, vEdge-2 constructs tunnel headers and sends ICMP Request to vEdge-1 via Public-Internet using MPLS Label 1003 as a VPN identifier. Routers in Internet routes packet based on the outer destination IP address. When vEdge-1 receives the packet, it notices that the destination IP address is its’ Public IP address. It first removes the outer IP header. Then it checks the tunnel header. Based on the Label value 1003, it knows that packet belongs to VPN 10. It consults the VPN 10 RIB and routes the packet to Border-PxTR-13. The ingress interface on Border-PxTR-13 belongs to VRF 100_NWKT that belongs to LISP Instance 100. It checks the Instance 100 specific LISP mapping in order to know how it should route the packet. The LISP mapping Database does not contain the information because this is the first packet to destination 172.16.100.10. Border-PxTR-13 sends a LISP Map-Request message to MapSrv-22, which replies with a LISP Map-Reply message, where it describes the RLOC of Edge-xTR-11 that has registered the IP address 172.16.100.10. I have excluded the Map-Request/Reply processes from figure 6-1 to keep the figure simple. Border-Leaf-13 encapsulates the ICMP Request packet with a tunnel header. It sets the Instance-Id 100 on the VXLAN header and adds the outer IP header where it uses the Edge-xTR-11’s IP address 192.168.0.13 as a destination address. Core-1 routes the packet to Edge-xTR-11 based on the outer IP header destination address. Edge-xTR-11 processes the ingress IP packet because the destination IP address belongs to it. Based on the destination UDP port 4789, it knows that the following header is a VXLAN header. Edge-xTR-11 knows that the LISP Instance-Id 100 is bind to BD 100. Because Edge-xTR-11 has an L3 interface in BD 100, it resolves the MAC address for the IP address 172.16.100.10 from the ARP table and the egress interface for the MAC from the MAC address table. EP1 processes the ICMP Request packet and sends the ICMP Reply to EP3.


Figure 6-1:End-to-End Data-Plane Operation.

 

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