More DHCP Snooping

This post is a follow up to Ethan’s post and Edward’s post. Both were very useful to me as I began to plan rolling out this feature. I wanted to verify something TimA said in the comments at the bottom of Ethan’s post, namely that a switch running DHCP Snooping will drop DHCP Discovers from […]

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Guy Morrell

Guy is a Network Architect and Engineer working at a major UK university. He blogs over at howfantastic.net mostly for his own benefit. From time to time he may write something which he thinks will be of interest to a wider audience and will post those blogs here at packetpushers.net, until someone tells him to stop.

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The post More DHCP Snooping appeared first on Packet Pushers Podcast and was written by Guy Morrell.

Install and configure vSphere Data Protection (VDP/VDPA)

SDN, APIs, and DevOps

SDN Lesson #1 – Introduction to Mininet

SDN Lesson #1 &#8211 Introduction to Mininet

Welcome to a new series of articles that will be structured as lessons with the target of bringing SDN closer to everyone's understanding. Each article will present a topic plus one or more exercises that will show that topic in action. The lessons will wrap up with some questions asking the readers to exercise on their own and provide the answers.

Working with VMware NSX – Logical to Physical connectivity

In our last post, we talked about how to deploy what I referred to as logical networking.  I classify logical networking as any type of switching or routing that occurs solely on the ESXi hosts.  It should be noted that with logical networking, the physical network is still used, but only for IP transport of overlay encapsulated packets. 

That being said, in this post I’d like to talk about how to connect our one of our tenants to the outside world.  In order for the logical tenant network to talk to the outside world, we need to find a means to connect the logical networks out to the physical network.  In VMware NSX, this is done with the edge gateway.  The edge gateway is similar to the DLR (distributed local router) we deployed in the last post, however there is one significant difference.  The edge gateway is in the data plane, that is, it’s actually in the forwarding path for the network traffic. 

Note – I will sometimes refer to the edge services gateway as the edge gateway or simply edge.  Despite both the edge services gateway and the DLR Continue reading

Network Automation: Shifting Fear Landscape

Networking and Cattle Prods

We have mostly all been burnt to a level of severity that we will or will not admit to by prodding and poking networks. Whether by an unexpected bug, lack of understanding of the thing we are poking, or sheer ‘bad luck’, there’s no avoiding it.

Being burnt by a network is almost like being zapped by a cattle prod. It doesn’t take many times before your brain rewires itself to avoid getting burnt, unless you’re a network masochist, in which case, you’re a special breed. This rewiring has resulted in using the CLI as an investigatory and validation tool as well as a configuration access method. What was that keyword again?

show ip bgp neighbor ?

Due to mistrust in the documentation, lack of desire or over trusting the CLI, our brains have become used to this behaviour and complacency has set in.

As we shift from configuring network elements manually to configuring them by automated template generation and structured API calls, will our well understood knowledge of a networking operating system with all of it’s caveats and nuances become redundant along with our bad habits? So do we just trust an amorphous piece of software Continue reading

Google Now Factoring HTTPS Support Into Ranking; CloudFlare On Track to Make it Free and Easy

As of today, there are only about 2 million websites that support HTTPS. That's a shamefully low number. Two things are about to happen that we at CloudFlare are hopeful will begin to change that and make everyone love locks (at least on the web!).

CC BY 2.0 by Gregg Tavares

Google Ranks Crypto

First, Google just announced that they will begin taking into account whether a site supports HTTPS connections in their ranking algorithm. This means that if you care about SEO then ensuring your site supports HTTPS should be a top priority. Kudos to Google to giving webmasters a big incentive to add SSL to their sites.

SSL All Things

Second, at CloudFlare we've cleared one of the last major technical hurdle before making SSL available for every one of our customers -- even free customers. One of the challenges we had was ensuring we still had the flexibility to move traffic to sites dynamically between the servers that make up our network. While we can do this easily when traffic is over an HTTP connection, when a connection uses HTTPS we need to ensure that the correct certificates are in place and loaded into memory Continue reading

BGP Security Vulnerabilities a Growing Concern

BGP Security Vulnerabilities a Growing Concern

Border Gateway Protocol (BGP), the protocol that connects different networks together, was not designed with security in mind. It is easy to take down portions of the Internet by announcing illegitimate routes to those parts (referred to as route hijacking). A classic example of this attack is a widely popularized incident a few years ago by a Pakistani service provider. The Pakistan government wanted to block YouTube internally. The service providers there injected a BGP route for YouTube and directed YouTube traffic to nowhere. This route somehow leaked outside of Pakistan, and was carried by many service providers across the Internet. This resulted, in effect, in YouTube’s removal from the Internet. 

These incidents, many not as high-profile as the YouTube incident, are routine and go back as far as I can remember. The first incident I am aware of is a dial-up Internet provider in Florida taking down the MIT network in the pre-1994, non-commercial era Internet. Early on, these incidents were results of honest configuration mistakes or fat fingering of wrong BGP configuration knobs. 

As we all know, the days of Internet innocence Continue reading

Network ping with delay, jitter and MOS

Understanding IPv6: A Sniffer Full Of 3s

Screen Scraping: Still Sucks

I’ve written before about “Why Screen Scraping Sucks.” Well, I can report that nothing has changed. It still sucks. This time I got caught out by the changed behaviour of the “logging host” command.

Compliance Checks

At a customer site I use HP IMC to perform compliance checks across HP and Cisco networking gear. This has a set of rules that get run against the latest device backups. I have various rules that look for specific patterns – making sure they do, or don’t exist, as required.

My systems should all have two log servers defined. The configs should look something like this:

Rack1SW1#sh run | inc ^logg
logging 1.1.1.1
logging 2.2.2.2

So I defined an IMC compliance rule that looked for the existence of “logging 1.1.1.1″ and “logging 2.2.2.2″. I’m using the Advanced mode, which uses regex matching, so I need to escape the “.”.

This worked well. It alerted on systems that had the incorrect (or no) destinations defined.

Wait a minute…I thought you said “logging host”?

Turns out that “logging X.X.X.X” was the original form of this command. At 12.3(14)T, Cisco changed Continue reading

CloudFlare Now Supports WebSockets

CC BY 2.0 from Brian Snelson

I'm pleased to announce that CloudFlare now supports WebSockets. The ability to protect and accelerate WebSockets has been one of our most requested features. As of today, CloudFlare is rolling out WebSocket support for any Enterprise customer, and a limited set of CloudFlare Business customers. Over the coming months, we expect to extend support to all Business and Pro customers.

We're rolling out WebSockets slowly because it presents a new set of challenges. The story below chronicles the challenges of supporting WebSockets, and what we’ve done to overcome them.

The Web Before WebSockets

Before diving into WebSockets, it's important to understand HTTP—the traditional protocol of the web. HTTP supports a number of different methods by which a request can be sent to a server. When you click on a traditional link you are sending a GET request to a web server. The web server receives the request, then sends a response.

When you submit a web form (such as when you're giving your username and password when logging into an account) you use another HTTP method called POST, but the interaction is functionally the same. Your browser (called the ‘client’) sends data to Continue reading

A Full Year of Commercially Available Cumulus Linux Brings Us to Version 2.2

It’s been about one year since we released Cumulus Linux commercially to the market.

Cumulus Linux proved itself quickly as a powerful alternative to traditional networking approaches — not only for the choice it provided with a disaggregated model (choice of both networking hardware and networking OS) or the new business model it provided (a software-only solution with a transparent pricing model) — but also because for the first time, the operating system was a true Linux OS, one that is managed just like Linux on servers, thereby solving many customer challenges around IT automation with tools such as Puppet, Chef, Ansible, Salt, Graphite, and Ganglia readily available on networking platforms. Soon, cloud providers adopted Cumulus Linux and took advantage of various tools to automate rack provisioning, orchestrate switches like servers, and integrate networking with existing workflows.

Cumulus Linux 2.0 brought support for the latest industry-standard hardware platforms with Trident II-based switches and the latest technologies with hardware accelerated VXLANs and Layer 2 gateway integration with network virtualization providers such as VMware NSX. Since then, Cumulus Networks has added many platforms to the HCL, with major partners such as Dell on board, and has had broad coverage for modern Continue reading

ifupdown2, a New Network Interface Manager for Cumulus Linux

VMware NSX Use Case – Simplifying Disaster Recovery (Part 2)

Nicolas Vermandé (VCDX#055) is practice lead for Private Cloud & Infrastructure  at Kelway, a VMware partner. Nicolas covers the Software-Defined Data Center on his blog www.my-sddc.om,

This is Part 2 in a series of posts the describes a specific use case for VMware NSX in the context of Disaster Recovery. Here’s part 1,

++++++++++++++++++++++++++++++++++

Deploying the environment

Now let’s see have a closer look at how to create this environment. The following picture represents the vSphere logical architecture and the associated IP scheme…

… and the networks mapping:

First of all you have to create three vSphere clusters: one Management Cluster and two Compute Clusters, as well as  two distinct VDS, within the same vCenter. Each Compute cluster will be connected to the same VDS. One cluster will represent DC1, and the other one will represent DC2. The second VDS will connect to the Management and vMotion networks. Also, you have to create a couple of VLANs: one VLAN for VTEPs, used as the outer dot1q tag to transport VXLAN frames, two external transit VLANs to allow the ESGs to peer with your IP core and VLANs for traditional vSphere functions, such as Management, vMotion and IP storage if Continue reading

IPv6 and the VCR

IPv6 isn’t a fad.  It’s not a passing trend that will be gone tomorrow.  When Vint Cerf is on a nationally televised non-technical program talking about IPv6 that’s about as real as it’s going to get.  Add in the final depletion of IPv4 address space from the RIRs and you will see that IPv6 is a necessity.  Yet there are still people in tech that deny the increasing need for IPv6 awareness.  Those same people that say it’s not ready or that it costs too much.  It reminds me of a different argument.

IPvcr4

My house is full of technology.  Especially when it comes to movie watching.  I have DVRs for watching television, a Roku for other services, and apps on my tablet so the kids can watch media on demand.  I have a DVD player in almost every room of the house.  I also have a VCR.  It serves one purpose – to watch two movies that are only available on a video tape.  Those two movies are my wedding and the birth of my oldest son.

At first, the VCR stated connected to our television all the time.  We had some movies that we Continue reading

Juniper EX – Private vlans

DDoS and Geopolitics – Attack analysis in the context of the Israeli-Hamas conflict

Since its inception, the ASERT team has been looking into politically motivated DDoS events [1] and continues to do so as the relationship between geopolitics and the threat landscape evolves [2]. In 2013, ASERT published three situational threat briefs related to unrest in Syria [3] and Thailand [4] and threat activity associated with the G20 summit [5].  Recently, other security research teams, security vendors and news agencies have posited connections between “cyber” and geopolitical conflicts in Iraq [6], Iran [7], and Ukraine [8] [9].

Given the increasing connections being made between security incidents and geopolitical events, I checked Arbor’s ATLAS data to look at DDoS activity in the context of the current conflict between Israel and Hamas. Arbor’s ATLAS initiative receives anonymized traffic and DDoS attack data from over 290 ISPs that have deployed Arbor’s Peakflow SP product around the globe. Currently monitoring a peak of about 90 Tbps of IPv4 traffic, ATLAS see’s a significant portion of Internet traffic, and we can use that to look at reported DDoS attacks sourced from or targeted at various countries.

Israel as a Target of DDoS Attacks

Frequency

Figure 1 depicts the number of reported DDoS attacks initiated against Israel per Continue reading

“What Might Have Been?” Is The Wrong Question