Replay pcap files using sflowtool


It can be very useful to capture sFlow telemetry from production networks so that it can be replayed later to perform off-line analysis, or to develop or evaluate sFlow collection tools. 
sudo tcpdump -i any -s 0 -w sflow.pcap udp port 6343
Run the command above on the system you are using to collect sFlow data (if you aren't yet collecting sFlow, see Agents for suggested configuration settings). Type Control-C to end the capture after 5 to 10 minutes.  Copy the resulting sflow.pcap file to your laptop. 
docker run --rm -it -v $PWD/sflow.pcap:/sflow.pcap sflow/sflowtool \
  -r /sflow.pcap -P 1
Either compile the latest version of sflowtool or, as shown above, use Docker to run the pre-built sflow/sflowtool image. The -P (Playback) option replays the trace in real-time and displays the contents of each sFlow message. Running sflowtool using Docker provides additional examples, including converting the sFlow messages into JSON format for processing by a Python script. 
docker run --rm -it -v $PWD/sflow.pcap:/sflow.pcap sflow/sflowtool \
  -r /sflow.pcap -f 192.168.4.198/6343 -P 1
The -f (forwarding) option takes an IP address and UDP port number as arguments, in this Continue reading

Using the Continue VSCode Extension and Local LLMs for Improved Coding

Using the Continue VSCode Extension and Local LLMs for Improved Coding

Welcome back to another post on local LLMs. In this post, we’ll look at setting up a fully local coding assistant inside VSCode using the Continue extension and Ollama. Let’s get started.

As always, if you find this post helpful, press the ‘clap’ button on the left. It means a lot to me and helps me know you enjoy this type of content.

Overview

We’ve covered Ollama and Local LLMs in previous blog posts (linked below), but here’s a quick summary.

Ollama is a tool that lets you run large language models (LLMs) directly on your local machine. Local LLMs are language models that run on your computer instead of relying on cloud-based services like ChatGPT. This means you can use them without sending your data to external servers, which is great for privacy. They also work offline, so you’re not dependent on an Internet connection.

That said, it’s important to note that local models, especially on smaller setups, won’t match the speed or performance of cloud-based models like ChatGPT. These cloud models are powered by massive infrastructure, so they’re faster and often more accurate. However, the trade-off is privacy and offline access, which local LLMs provide.

In Continue reading

Using Ollama with a Web-Based GUI

Using Ollama with a Web-Based GUI

When I first started using local LLMs with Ollama, I quickly realised it relies on a command-line interface to interact with the models. It also comes with an API, but let’s be honest, most of us, myself included, prefer a GUI, much like the one ChatGPT provides. There are plenty of options available, but I decided to try Open Web GUI. In this blog post, we’ll explore what Open-WebGUI is and how simple it is to set up a web-based interface for your local LLMs.

As always, if you find this post helpful, press the ‘clap’ button on the left. It means a lot to me and helps me know you enjoy this type of content.

Overview

Ollama is a tool for running local LLMs, offering privacy and control over your data. Out of the box, it lets you interact with models via the terminal or through its API. Installing Ollama is straightforward, and if you’d like a detailed guide, check out my other blog post which is linked below.

This blog post assumes you already have Ollama set up and running. For reference, I’m running this on my MacBook (M3 Pro with 18GB of RAM).

open-webui

Open Continue reading

Running Large Language Models (LLM) on Your Own Machine Using Ollama

Running Large Language Models (LLM) on Your Own Machine Using Ollama

I’m going to start by saying I’m totally new to LLMs and running them locally, so I’m not going to pretend like I know what I am doing. I’ve been learning about Ollama for some time now and thought I would share it with my readers as always. This is such an interesting topic and I’m ready to go into the rabbit hole.

As always, if you find the content useful, don’t forget to press the ‘clap’ button to your left. This is one way for me to know that you like this type of content, which means a lot to me. So, let's get started.

Large Language Models (LLMs)

LLMs, or Large Language Models, are a type of artificial intelligence designed to process and generate natural language. They are trained on vast amounts of text data, enabling them to understand context, identify patterns, and produce human-like responses. These models can perform various tasks such as answering questions, translating languages, summarising text, generating creative content, and assisting with coding. LLMs have gained significant attention in recent years due to their impressive performance and versatility.

Palo Alto URL Filtering and SSL Decryption
Without SSL decryption, the Palo Alto firewall Continue reading

N4N011: What’s the Difference Between LAG, MLAG, MC-LAG, and Stacking?

In today’s episode, we address listener Kieren’s question about the differences between LAG, MLAG, MC-LAG, and stacking. We tackle the nuances of Link Aggregation (LAG) and the Link Aggregation Control Protocol (LACP), and explain their roles in redundancy and bandwidth efficiency. We also discuss the complexities and differences among vendors and overall benefits of Multi-Chassis... Read more »

IBM Takes The Patient Path To Future GenAI Profits

While the hyperscalers and cloud builders provide the best indicator of what it takes to create state of the art GenAI models and the infrastructure to train them as well as to put them into production for practical use through an API interface, perhaps IBM is one of the best leading indicators for how GenAI will slowly be adopted by the enterprises of the world within their own organizations. …

IBM Takes The Patient Path To Future GenAI Profits was written by Timothy Prickett Morgan at The Next Platform.

The Curious Case of the BGP Connect State

I got this question from Paul:

Have you ever seen a BGP peer in the “Connect” state? In 20 years, I have never been able to see or reproduce this state, nor any mention in a debug/log. I am starting to believe that all the documentation is BS, and this does not exist.

The BGP Finite State Machine (FSM) (at least the one defined in RFC 4271 and amended in RFC 9687) is “a bit” hard to grasp but the basics haven’t changed from the ancient days of RFC 1771:

Read more …

Azure Can’t Make Up For On Premise Profit Decline At Microsoft

If you think it might be difficult to sell companies general purpose servers when they are frenzied about GenAI and trying to figure out how to get GPU-accelerated systems, you ought to try to convince the same companies to upgrade to Windows Server 2025, which launched last November. …

Azure Can’t Make Up For On Premise Profit Decline At Microsoft was written by Timothy Prickett Morgan at The Next Platform.

NAN084: From GitNops Zero to Hero

Are you ready to go from zero to hero in GitNops? On today’s podcast, we talk with Tom McGonagle, who shares and explains git, CI/CD and DevOps and how that all fits into network engineering. The conversation also covers the evolution of containerization and Kubernetes, highlighting their roles in modern network automation.  Tom also encourages... Read more »

ByteDance to Network a Million Containers with Netkit

Engineers from the Chinese social media conglomerate ByteDance are taking early advantage of a recently released feature of the Linux kernel called netkit that provides a faster way for containers to communicate with each other across a cluster. First released in Linux kernel 6.7 in December 2023, netkit is a now-discontinued Netkit that was used to create virtual networks on a single server) and has been touted as a way to streamline container networking. Like the rest of the cloud native world, ByteDance uses Virtual Ethernet (had a number bottlenecks that slowed communication rates across containers. In fact, veth requires each packet to traverse two network stacks — one of the sender and the other of the recipient — even if the two containers communicating were on the same Continue reading

Cisco Modeling Labs and Infrastructure-as-Code

Dalton Ortega, Cisco Modeling Labs Product Manager, sent me the following email as a response to my Configuring IP Addresses Won't Make You an Expert blog post:

First, your statement on Autonetkit is indeed correct. We had removed that from the product due to lack of popularity. That being said, in our roadmap we are looking at methods to reintroduce on-the-fly configuration as well as enhancing our sample labs library to make getting started with CML easier.

Secondly, CML can be run in full IaC mode because of the API-first build. In fact, many of our customers are using CML as an automated test/validation bed for their CI/CD pipelines. Tools like Ansible and Terraform are available to facilitate this inside CML too. For more details, read:

It seems it should be relatively easy to create a cml provider to generate a Terraform file from the netlab topology and use it to start a lab in CML. Any volunteers?

PP047: Why Packet Analysis (and Wireshark) Should Be In Your Security Toolkit

Don’t underestimate the value of packet analysis in your security strategy. And if you’re analyzing packets, the open-source Wireshark software is a go-to tool. On today’s episode, we talk with Chris Greer, a Wireshark trainer and consultant specializing in packet analysis. Chris explains the critical role of packet analysis in cybersecurity, particularly in threat hunting... Read more »

NB511: Cisco Sells Security Blanket for AI Nightmares; Stratoshark Captures System Calls

Take a Network Break! We start with critical vulnerabilities affecting the Android OS, Cisco Meeting Management, and SonicWall, and then discuss a report that tens of thousands of Fortinet security appliances still haven’t been patched despite active exploits. Palo Alto Networks releases an open API to make it easier for developers to access Quantum Random... Read more »

HS093: Strategic Trust-Building Among Ops, Engineering, Architecture – and Leadership

Billy Joel had it right: It’s a matter of trust. Too often Operations, Engineering, and Architecture teams don’t trust one another–and nobody trusts leadership (and vice versa!). Special guest (and PacketPushers host) Scott Robohn joins us to talk about how to build trust, and the special role of an Operations Architect. Episode Guest: Scott Robohn, ... Read more »

HW044: Unpacking NETGEAR’s Enterprise Wireless and Wired Portfolio (Sponsored)

NETGEAR is known for consumer networking products, but it also offers a robust porfolio of wireless and wired networking products designed for the enterprise. On today’s Heavy Wireless, sponsored by NETGEAR, we take a close look at the hardware, software, and services that NETGEAR offers to enterprise customers. That includes Wi-Fi 7 APs, a full... Read more »

The Coming Age Of The Internet Of Agents

Almost a year ago, executives, researchers, and developers within the Outshift group of Cisco Systems – an incubation unit focused on such advanced technologies as AI and quantum computing – began batting about the idea of a network infrastructure connecting vast numbers of AI agents from multiple vendors or organizations, allowing those AI agents to automatically communicate, work together, and solve complex problems for enterprises. …

The Coming Age Of The Internet Of Agents was written by Jeffrey Burt at The Next Platform.

A diversity of downtime: the Q4 2024 Internet disruption summary

Cloudflare’s network spans more than 330 cities in over 120 countries, where we interconnect with over 13,000 network providers in order to provide a broad range of services to millions of customers. The breadth of both our network and our customer base provides us with a unique perspective on Internet resilience, enabling us to observe the impact of Internet disruptions at both a local and national level, as well as at a network level.

As we have noted in the past, this post is intended as a summary overview of observed and confirmed disruptions, and is not an exhaustive or complete list of issues that have occurred during the quarter. A larger list of detected traffic anomalies is available in the Cloudflare Radar Outage Center.

In the third quarter we covered quite a few government-directed Internet shutdowns, including many intended to prevent cheating on exams. In the fourth quarter, however, we only observed a single government-directed shutdown, this one related to protests. Terrestrial cable cuts impacted connectivity in two African countries. As we have seen multiple times before, both unexpected power outages and rolling power outages following military action resulted in Internet disruptions. Violent storms and an earthquake Continue reading

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