Combining URL Categories on Palo Alto

Combining URL Categories on Palo Alto

We know that in Palo Alto, or in any NGFW, we can allow or block various URL categories. Speaking specifically about the Palo Alto firewall, let's say you have a strict URL filtering policy and decide to block the 'Shareware and Freeware' category.

When you do this, you'll likely have frustrated users complaining that they can't access sites like GitHub, for example.

But, What Did I Do?

So, what did I do now to cause another network issue? Well, Palo Alto categorizes github.com as 'Shareware and Freeware', so the firewall simply blocks it. There’s a high chance that many other useful sites will get blocked too.

Combining URL Categories on Palo Alto
Combining URL Categories on Palo Alto

A quick fix is to create a Custom URL Category and add the GitHub URL to it. However, this isn’t a scalable solution.

For instance, if I start with *.github.com, the firewall may block github.com. Then, if I add github.com, the firewall might block URLs like www.github.githubassets.com. To address this, I’d need to use a different wildcard, but we can’t keep doing this for every affected site.

Combining URL Categories on Palo Alto
Combining URL Categories on Palo Alto

Combining URL Categories

Instead of managing each URL individually like before, we Continue reading

BGP Zombies at NANOG 93

The internet is held together by the Border Gateway Protocol (BGP). Its a flooding protocol whose intended outcome is to ensure that every BGP speaker has the same information base as every other BGP speaker. What happens when this flooding algorithm fails? What happens if the information in a BGP speaker falls out of sync?

Large Language Models (LLM) – Part 1/2: Word Embedding

Introduction

This chapter introduces the basic operations of Transformer-based Large Language Models (LLMs), focusing on fundamental concepts rather than any specific LLM, such as OpenAI’s GPT (Generative Pretrained Transformer).The chapter begins with an introduction to tokenization and word embeddings, which convert input words into a format the model can process. Next, it explains how the transformer component leverages decoder architecture for input processing and prediction. 

This chapter has two main goals. First, it explains how an LLM understands the context of a word. For example, the word “clear” can be used as a verb (Please, clear the table.) or as an adjective (The sky was clear.), depending on the context. Second, it discusses why LLMs require parallelization across hundreds or even thousands of GPUs due to the large model size, massive datasets, and the computational complexity involved.


Tokenizer and Word Embedding Matrix

As a first step, we import a vocabulary into the model. The vocabulary used for training large language models (LLMs) typically consists of a mix of general and domain-specific terms, including basic vocabulary, technical terminology, academic and formal language, idiomatic expressions, cultural references, as well as synonyms and antonyms. Each word and character is Continue reading

From Python to Go 014. Templating Configuration Files.

Hello my friend,

Congratulations if you reach this blog post starting from the beginning of our series. I look in the list of topic I’m going to cover with respect Python to Go (Golang) transition and I see that I’ve already written more than 50% of blog posts; so we are over the half! Secondly, from today we start talking solely about practical network and IT infrastructure automation topics, as all the foundational things are already covered, such as data types, code flow control, reading and parsing files, using CLI arguments, exceptions handling to name a few. Today we’ll talk about how we can template text files. With respect to network and IT infrastructure automation that means we look how to prepare configuration of our network devices, Linux servers or further appliances.

Isn’t AI Going to Replace All Software Developers Anyway?

Almost daily I see in LinkedIn posts about how cool AI is in generating code. It is cool, I agree with that. And I myself use Co-pilot for my private projects for already more than a year and ChatGPT for certain things. However, my experience is that at this stage they don’t yet replace engineers Continue reading

Resolving a Mutual TLS session resumption vulnerability

On January 23, 2025, Cloudflare was notified via its Bug Bounty Program of a vulnerability in Cloudflare’s Mutual TLS (mTLS) implementation. 

The vulnerability affected customers who were using mTLS and involved a flaw in our session resumption handling. Cloudflare’s investigation revealed no evidence that the vulnerability was being actively exploited. And tracked as CVE-2025-23419, Cloudflare mitigated the vulnerability within 32 hours after being notified. Customers who were using Cloudflare’s API shield in conjunction with WAF custom rules that validated the issuer's Subject Key Identifier (SKI) were not vulnerable. Access policies such as identity verification, IP address restrictions, and device posture assessments were also not vulnerable.

Background

The bug bounty report detailed that a client with a valid mTLS certificate for one Cloudflare zone could use the same certificate to resume a TLS session with another Cloudflare zone using mTLS, without having to authenticate the certificate with the second zone.

Cloudflare customers can implement mTLS through Cloudflare API Shield with Custom Firewall Rules and the Cloudflare Zero Trust product suite. Cloudflare establishes the TLS session with the client and forwards the client certificate to Cloudflare’s Firewall or Zero Trust products, where customer policies are enforced.

mTLS operates Continue reading

Amazon Will Spend Nearly A Year Of AWS Revenue On AI Investments

There is a bit of AI spending one-upmanship going on among the hyperscalers and cloud builders – and now the foundation model builders who are partnering with their new sugar daddies to be able to afford to build vast AI accelerator estates to push the state of the art in model capabilities and intelligence. …

Amazon Will Spend Nearly A Year Of AWS Revenue On AI Investments was written by Timothy Prickett Morgan at The Next Platform.

TNO015: Revolutionizing Telecom with NetOps Automation and Collaboration

Today’s episode with guest Joan Garcia provides valuable insights into the complexities of modern network operations at a telco, the importance of collaboration across technical domains, and the strategic decisions that drive innovation in the telecom industry. Joan’s experiences and perspectives offer ideas for navigating the challenges of integrating different layers of network architecture while... Read more »

Cloudflare incident on February 6, 2025

Multiple Cloudflare services, including our R2 object storage, were unavailable for 59 minutes on Thursday, February 6, 2025. This caused all operations against R2 to fail for the duration of the incident, and caused a number of other Cloudflare services that depend on R2 — including Stream, Images, Cache Reserve, Vectorize and Log Delivery — to suffer significant failures.

The incident occurred due to human error and insufficient validation safeguards during a routine abuse remediation for a report about a phishing site hosted on R2. The action taken on the complaint resulted in an advanced product disablement action on the site that led to disabling the production R2 Gateway service responsible for the R2 API.  

Critically, this incident did not result in the loss or corruption of any data stored on R2. 

We’re deeply sorry for this incident: this was a failure of a number of controls, and we are prioritizing work to implement additional system-level controls related not only to our abuse processing systems, but so that we continue to reduce the blast radius of any system- or human- action that could result in disabling any production service at Cloudflare.

What was impacted?

Continue reading

How Much Money Does Arm Make In The Datacenter?

As we have been saying for quite some time, when it comes to datacenter CPUs, we think that homegrown Arm processors (as well as those made by independents Ampere Computing and Huawei Technologies) will eventually represent at least half of the computing capacity that the hyperscalers and major cloud builders install. …

How Much Money Does Arm Make In The Datacenter? was written by Timothy Prickett Morgan at The Next Platform.

Automation Workflow with Infrahub, Nornir & Jinja2

Originally published in https://www.opsmill.com/simplifying-network-automation-workflows-with-infrahub-nornir-and-jinja2/
Automation Workflow with Infrahub, Nornir & Jinja2

In this blog post, we will explore how InfraHub integrates with Jinja2 and Nornir to simplify network automation workflows. To demonstrate, we'll add two Arista devices to InfraHub, treating them as basic access switches. We'll then input the necessary details for these devices to generate configurations. We'll focus on creating VLAN and some interface configurations to keep it simple.

For each device, we'll assign a primary IP (used for SSH), configure a few interfaces with descriptions, and specify an untagged VLAN for each interface. Additionally, we'll define these VLANs globally in InfraHub (not tied to any specific device). A Jinja2 template will then use this information to generate configurations for each device. Finally, we'll use the nornir-infrahub plugin as the inventory source and Napalm to push the generated configurations to each device.

Getting Started with Infrahub
If you’re in the network automation space or attended one of the last two Autocon events, you might have come across a new tool called ‘Infrahub’ from OpsMill
Automation Workflow with Infrahub, Nornir & Jinja2PacketswitchSuresh Vina
Automation Workflow with Infrahub, Nornir & Jinja2

Prerequisites

This blog post assumes you are somewhat familiar with Git and Docker. If you’re new to InfraHub, don’t worry, you should still be able to follow Continue reading

Group Similar Links in netlab Topologies

In the Concise Link Descriptions blog post, I described various data formats that you could use to concisely list nodes attached to a link. Today, we’ll focus on a mechanism that helps you spot errors in your topology: a dictionary of links.

Imagine you have a large topology with dozens of links, and you get an error saying, “there is this problem with links[17]”. It must be great fun counting the links to find which one triggered the error, right?

Read more …

Trying to Automate Palo Alto Firewall Objects/Rules Cleanup

Trying to Automate Palo Alto Firewall Objects/Rules Cleanup

In this blog post, we will walk you through how to clean up Palo Alto Firewall Objects and Rules using a simple Python script. The script is designed to search for a specific IP address or an entire subnet and remove any associated references.

The Problem

Have you ever found yourself in a situation where you've decommissioned a server or maybe even an entire subnet, and now you're faced with the task of cleaning up your firewall? If you're using Palo Alto, you probably know that you can't just remove an address object; you first need to eliminate all its references from address groups and rules.

This can become especially cumbersome if a single object is referenced in multiple places—you'll have to remove them one by one. Now, imagine having to do this for an entire subnet where multiple objects are involved. If this sounds familiar, read on to find out how to make this process easier using a simple Python Script.

If you are looking for a more sophisticated solution, feel free to check my other blog post on how to achieve this via the 'pan-os-php' library.

Palo Alto Object and Policy Cleanup with pan-os-php
If you work with Continue reading

D2DO264: Serverless Goes Mainstream

Serverless is mature enough now to be a mainstream choice for application development. But that doesn’t mean interesting things aren’t happening. Benjamen Pyle joins Kyler and Ned on Day Two DevOps to talk about the potential for small vendors and startups to develop high-quality services purpose-built to solve specific problems. They also discuss the benefits... Read more »
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