How I Passed the CCIE Collaboration Lab Exam

Having passed the CCIE Voice 10 years ago, and having taught on the technologies surrounding both Voice and Collaboration ever since, one might think that the exam would be easy to pass. I can assure you that no matter how much you know, no CCIE exam is easy to pass. Cisco doesn’t allow them to be. Every CCIE track requires hard work and preparation, even if it may, at first glance, seem somewhat of a repeat of things you already know. You may ask since I had the CCIE Voice already, why I didn’t simply take the Collaboration Written exam and convert my cert to a CCIE Collaboration? The answer I think is pretty straightforward – it’s the challenge!! Seeing if you still have it 10 years later. Seeing if what you’ve been teaching your students for 10 years is still up to par and still relevant. To take you back to when I passed CCIE Voice ten years ago, the track was literally brand new that year, and Cisco was testing on CallManager version 3.3, SIP wasn’t anywhere to be found, and creating a hunt group meant tweaking Attendant Console to make it do things it shouldn’t ever Continue reading

Juniper Password Recovery

I recently purchased a Juniper J2320 from eBay for a fair price.  I know it is an older router, but it has the features I need in order to test and write a few things.  When I received the router it was not sent with a wiped config, so I was unable to log into […]

Network Break 14

The Network Break isn't broken and returns for another week with a closer look at the news.

Author information

Greg Ferro

Greg Ferro is a Network Engineer/Architect, mostly focussed on Data Centre, Security Infrastructure, and recently Virtualization. He has over 20 years in IT, in wide range of employers working as a freelance consultant including Finance, Service Providers and Online Companies. He is CCIE#6920 and has a few ideas about the world, but not enough to really count.

He is a host on the Packet Pushers Podcast, blogger at EtherealMind.com and on Twitter @etherealmind and Google Plus.

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The post Network Break 14 appeared first on Packet Pushers Podcast and was written by Greg Ferro.

New Feature in Cumulus Linux 2.2: sFlow

sFlow is an open protocol, newly supported in Cumulus Linux 2.2, that enables a collector to determine what is going on in a complex network.

It is used to collect statistics, such as packet counts, error counts, CPU usage, etc from a large number of individual switches. What is especially interesting is that it can be used to collect sampled packets (usually only the first n bytes, containing the header), along with some metadata about those packets.

Bringing sFlow to Cumulus Linux was particuarly easy, because “hsflowd” was already available for implementing sFlow support on Linux servers. We were able to reuse that existing code, with extremely minimal modification, to implement sFlow on our Linux based switches.

sFlow allows a collector to get a statistical view of what is going on in a collection of switches, approaching per-flow granularity. This is extremely useful information to present to users for capacity planning and debugging purposes, but things really get interesting when the collector can make decisions based on the information.

For example, our friends at inMon implemented detection of elephant flows (high bandwidth), followed by marking those flows on the switch at network ingress for special QoS handling. This nearly Continue reading

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 […]

Author information

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)

The vSphere Data Protection appliance allows to backup virtual machines with a built-in tool instead of a third-party backup product. VDP is available on all vSphere editions but Essentials Kit. Moreover VDP can be extended to VDPA (vSphere Data Protection Advanced). Basically VDPA has the same features of VDP, except: VDPA has a per-CPU (socket) license, VDP […]
(Visited 251 times since 2013-06-04, 9 visits today)

SDN, APIs, and DevOps

There was a recent blog by Mark Burgess, founder and creator of CFEngine. It is a must read (on his personal blog).  He really makes you think where we are as an industry, question if we are on the right path, and quite frankly calling out certain technologies as pity attempts compared to what is needed. Regardless of all that, we cannot forget one key point, the industry is in fact moving forward right now. 
As I read his post, I remembered a conversation that I saw on twitter not too long between John Willis, Lori MacVittie, and Joe Onisick. It was more or less on the intersection of SDN and DevOps. 

The article by Burgess and the Twitter conversation really got me thinking. 

When you combine these interactions, even at the highest levels, you have to wonder, what is the right approach from both a vendor (product) and user standpoint? Are we on the right path? Do we have it all wrong? Must we fail first before getting it right?

SDN Will Simplify

SDN controllers will totally simplify things, but even then, the APIs they expose are arguably too low level for the average consumer of Continue reading

SDN Lesson #1 – Introduction to Mininet

Intro 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. As you see, the approach is pretty similar... [read more]

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

by Cengiz Alaettinoglu, CTO - August 6, 2014

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

I found a Python script to ping a remote system. I added a very short piece of code to print out Jitter and MOS data. # ./ping.py -c 1000 -t 1 -d 8.8.8.8 Statistics for 8.8.8.8: - packet loss: 2 (0.20%) - latency (MIN/MAX/AVG): 46/281/52 - jitter: 2.1583 - MOS: 4.3 A Nagios compatibile output is […]
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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

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