Packet Pushers Podcast» Blogs

Network Design Challenge – Small Little Clouds

Mike Kantowski — Thu, 23 May 2013 13:19:10 +0000

At work, we’ve been getting ready to deploy a few different cluster technologies. One is a set of KVM hosts to offer VMaaS functionality to end users. Another is a CEPH cluster (http://ceph.com/) which is smart distributed storage. The third is a Hadoop cluster. Each of these initiatives popped up around the same time and [...]

Programming 101 for Network Engineers – Basic Language Elements & Concepts 2

Steven Iveson — Thu, 23 May 2013 13:07:22 +0000

Welcome to the fourth part of the Programming 101 for Network Engineers series and part two of the Basic Language Elements and Concepts article. The following overview of programming language elements and those found in part three will provide a good foundation that can be built upon as we move into other topics and the detail [...]

Review: ScienceLogic – One Network Management Tool to Rule Them All?

Lindsay Hill — Wed, 22 May 2013 23:00:20 +0000

ScienceLogic has been getting the right kind of press recently – e.g. they were a winner of Best of Interop 2013 – Management & Monitoring, and Infoworld had some rather nice things to say. They’ve got some high-profile customers too, such as Fasthosts and Equinix. But what exactly is their product all about, and is it any [...]

Mrs. Y’s Rules for Security Bloggers

Mrs. Y — Wed, 22 May 2013 11:54:52 +0000

Recently Greg Ferro published an e-book for bloggers, “Arse First Method of Technical Blogging.” It has some great suggestions (although I’m not sure what an arse is), but after reading it, I realized it really doesn’t apply to security blogging. Without further ado, here are some of my tips for good infosec blog posts. 1. [...]

SDN: Savior or Grifter?

Mrs. Y — Tue, 21 May 2013 12:14:10 +0000

Grift’s like anything else, Roy. You don’t stand still. You either go up or down. Usually down, sooner or later. Lilly Dillon from “The Grifters” At Interop this month, every vendor had product sheets that claimed, ”Now with SDN!” It’s the latest industry buzzword and I started to recall some previous one-hit wonders from the past. Remember [...]

Programming 101 for Network Engineers – Basic Language Elements & Concepts 1

Steven Iveson — Mon, 20 May 2013 12:10:39 +0000

Welcome to the third part of the Programming 101 for Network Engineers series. This is likely to be the most ‘straight up’ piece so far; all fact and almost no fun (but learning is right?). Sorry, but for now the comment and opinion need to be put aside as we get into some nitty-gritty. The following [...]

Two Hours, Two Days…

Russ White — Sun, 19 May 2013 15:09:38 +0000

It’s either two hours, two days, two weeks… or too long. Two things these last two weeks have brought this old saying to mind in full force. First, there is this interesting article about the woes of the Medicaid Management System in Tennessee. Here we have a program that has overrun it’s budget for multiple [...]

Shopping at the SDN App Store: What Enterprises Really Want?

Ethan Banks — Tue, 14 May 2013 12:10:55 +0000

I contributed 2 pieces to a Network World “digital spotlight” on software defined networking (SDN). SDN’s all the rage with marketing teams & the industry media. I’ve been contracted to write or contribute to a total of 3 large SDN pieces, including this one, over the next few months. And of course at Interop, you couldn’t walk [...]

Cisco OTV Implementation & Troubleshooting (Legacy Multicast Mode)

Ken Matlock — Tue, 14 May 2013 12:00:02 +0000

For the details on what Overlay Transport Virtualization (OTV) is and how it works on a high-level, see my previous blog entry about OTV 101. OTV troubleshooting requires a basic understanding of Multicast, as well as ISIS. In-depth troubleshooting on these subjects are not part of the scope of this document. This document will only [...]

Cisco OTV 101 (Legacy Multicast Mode): MAC Learning Process Walk

Ken Matlock — Mon, 13 May 2013 12:00:36 +0000

What is OTV? Overlay Transport Virtualization (OTV) is a Cisco-proprietary protocol suite that allows us to extend Layer 2 between datacenters with Layer 3 boundaries in between. It works by encapsulating the L2 packets into L3 multicast packets and sending them out to all other OTV AED’s (Authoritative Edge Devices, used for loop prevention). The [...]

Interop: Firewalls, Booth Babes and Unicorn Poop

Mrs. Y — Sun, 12 May 2013 19:37:40 +0000

Now that I’ve returned from the whirlwind that was Interop Las Vegas, I thought I’d share some thoughts about my experience as a speaker and attendee. First the good: The UBM staff was awesome and I appreciated the chance to pontificate on one of my favorite subjects, firewalls. Thanks to some quick thinking by the [...]

Book Review: A Primer of Multicast Routing

Russ White — Tue, 07 May 2013 17:25:37 +0000

I was recently in need of a refresher on multicast routing, so I picked up Eric Rosenberg’s A Primer of Multicast Routing (Springer Briefs in Computer Science). The overall plan of the book is excellent, starting with a basic overview of what multicast is (and does), including why multicast is more efficient than unicast for [...]

How to Turn Your IOS Router Into a Pr0n Server (Pr0n Not Included)

Ken Matlock — Tue, 07 May 2013 12:00:52 +0000

No, really! Did you know that your IOS-based router is capable as acting as a static webserver? Below you will find the steps necessary to turn a GNS/Dynamips box (or any ‘testlab’ machine) into something that can serve basic HTTP/HTTPS content. Due to the security implications of the steps below, it’s not recommended to do [...]

Getting the Most Out of SPAN or Mirror Ports

Darragh Delaney — Mon, 06 May 2013 17:30:21 +0000

In my previous blog post I looked at the benefits and limitations of SPAN ports. SPAN or mirror ports are a convenient way of getting access to network packets without having to be inline like a firewall. Once you have got your network packet source in place, the next question is, what applications are available [...]

Are You a Fuddy Duddy?

Russ White — Sat, 04 May 2013 14:21:57 +0000

This recent article from IEEE Spectrum discusses our impression that as we age, we lose the ability to learn quickly — fluid intelligence, as it’s called. An accompanying chart shows this in some degree through the skill of chess players across a range of ages. There’s something suspicious about this chart, though, and it’s pairing [...]

Machine Fragile: More Thoughts

Russ White — Thu, 02 May 2013 19:05:17 +0000

I just ran across a pointer to this research on Bruce Schneier’s blog: Networking system components that are well-behaved in separation may create counter-intuitive emergent system behaviors, which are not well-behaved at all. For example, cooperative behavior might unexpectedly break down as the connectivity of interaction partners grows. “Applying this to the global network of [...]

VMware VCDX Lab: The Hardware

Douglas Hanks — Wed, 01 May 2013 01:29:17 +0000

I have to admit I’m a big VMware fanboy. Wanting to master the art of virtualization, I’ve set out to build out a personal lab. My primary goal is to work my way up to the VCDX certification. The curious thing about building a VMware lab is that all parts need to be on the [...]

A Data Center Delivers Apps – So Shouldn’t We Monitor App Delivery?

Ethan Banks — Sat, 27 Apr 2013 20:45:17 +0000

Dinner with His Toadishness, Derick Winkworth, the other night rolled into a 3+ hour discussion of avant garde ways to do networking. One of the adjunct topics that came up was that of ownership within IT. Ownership is a complex problem in the data center, because there’s many complex technologies at work. No one single [...]

Machine Fragile

Russ White — Sat, 27 Apr 2013 01:11:05 +0000

Yesterday, a “breaking news” tweet at 1:07 PM EDT from the Associated Press reported that two explosions had occurred at the White House and President Obama had been injured. The news immediately sent the Dow Jones Industrial Average down 143 points, as this graph at the London Telegraph shows. There’s also a lovely animated display [...]

It Works and It Should Be Better

Greg Ferro — Fri, 26 Apr 2013 14:34:11 +0000

You say, “It works – don’t fix it.” I hear, “It works – don’t touch it.” I’m also thinking that if you don’t touch it, then it’s never upgraded or changed. Is a static, unchanged network the best you can do to support your business ? Are you happy with just doing more of the same [...]

Programming 101 for Network Engineers – Preparation

Steven Iveson — Tue, 23 Apr 2013 13:15:14 +0000

Okay, let’s say you’re convinced you need to learn to programme and you don’t want to be left behind. The earlier you start, the more you can pick up (and the sooner you’ll become consciously competent) at a pace that suits you. Hopefully, you’ll be able to blend this into your schedule with whatever else you [...]

What the Heck Is F5 Networks’ TMOS?

Steven Iveson — Sat, 20 Apr 2013 17:34:05 +0000

F5 Network’s Traffic Management Operating System (TMOS) is, first and foremost and for the sake of clarity, NOT an individual operating system. It is the software foundation for all of F5’s network or traffic (not data) products; physical or virtual. TMOS almost seems to be a concept rather than a concrete thing when you first try [...]

Cisco Nexus – Port “Inactive” Status

Ethan Banks — Thu, 18 Apr 2013 19:14:14 +0000

Quick notes on the “inactive” port status seen on the Cisco Nexus platform, which was perplexing the first time I ran into it. This isn’t a new status, existing on a variety of Cisco platforms for a long time now. As it happens, I’ve just not seen it that often historically. In dealing with the [...]

Fighting Stale Documentation

Keith Tokash — Sun, 14 Apr 2013 17:40:45 +0000

In my continuing series on the decidedly boring, I would like to discuss the subtle, yet paralyzing, evil of stale documentation. In my experience, stale documentation can be useful or it can be disastrous, depending on how much is wrong. Personally, when I see more than a couple of tiny mistakes in a diagram, spreadsheet, [...]

CCIE Security v4 Reading List – Update From the Program Manager

Ethan Banks — Sat, 13 Apr 2013 01:08:35 +0000

Because of my personal interest in the CCIE Security program (at least the written exam the next time I’m up for CCIE recert), I asked Nat Timms if there was an updated CCIE reading list. This list was recommended to me by Nat in her role as CCIE Security program manager; a big thanks to [...]

Programming 101 for Network Engineers – Why Bother?

Steven Iveson — Wed, 10 Apr 2013 12:00:58 +0000

Is this you perhaps? You’re the king of the network. You know it all inside out (your company and its processes too). You have every CLI mastered, you know the RPs you use in-depth, you’ve seen and used all the big management platforms, and you even know a fair bit about a few critical applications. [...]

Upgrading F5 BIGIP HA Pair From v10 to V11 – Ethan’s Notes

Ethan Banks — Wed, 10 Apr 2013 01:22:12 +0000

I recently completed a challenging upgrade on a pair of production F5 3600s running 10.2.0, going to 11.2.1 running the LTM module. In hindsight, it shouldn’t have been a challenging upgrade, but that was due to the things I learned along the way. Lessons Learned License reactivation. The upgrade document doesn’t say much about this. [...]

ONS 2013 Brings Together the Entire SDN Ecosystem on April 15-17

Sponsored Blog Posts — Mon, 08 Apr 2013 07:00:20 +0000

Software Defined Networking (SDN) is revolutionizing the traditional networking approaches that have become too complex, closed, proprietary and/or difficult to program. The technology has the potential to enable network innovation by allowing network owners and operators more control of their infrastructure, thus allowing customization, optimization, and the reduction in overall capital and operational expenses. SDN [...]

Wanted: OpenFlow Switch With ofp_action to Modify the Destination L3 Address

Tamihiro Yuzawa — Mon, 08 Apr 2013 03:00:04 +0000

This article is meant to serve in part as an appendix to my previous post on PacketPushers.net. Therefore, please take a moment to read this introduction of Sakura Internet’s DDoS detection and mitigation app if you haven’t already. At Sakura, we are in the process of implementing source-and-destination-based DDoS packet filtering that should be effective and [...]

Come to ONS 2013 April 15-17 & Plug-in to SDN

Sponsored Blog Posts — Wed, 03 Apr 2013 07:00:15 +0000

Software Defined Networking (SDN) is the buzzword on the mind of every player in the networking and telecom ecosystem; promises to revolutionize networking as we know it and will affect service provider networks, cloud networks and enterprise networks. Open Networking Summit (ONS) 2013 is the premier conference for SDN and Open Flow and has established [...]

Nuage Networks VSP – Delivers SDN in a Big Way – White Paper – Sponsored

Greg Ferro — Tue, 02 Apr 2013 15:00:00 +0000

Nuage Networks announces their Virtualised Services Platform and shows that SDN Networking is closer than you think. VSP is a multi-layer solution with a SDN app, controller & network agent with some technical chops. It's derived from Alcatel-Lucent's Service Routers and offers multi-data centre networking that's fully integrated with your MPLS WAN ? Find out more in the very first Packet Pushers Sponsored White Paper where we scratch it's technical under belly.

The Future of F5 Networks: SDN, iRules & Node.js

Steven Iveson — Tue, 02 Apr 2013 11:17:56 +0000

Unlike some others in the network industry (until lately at least), those dealing with F5 Networks’ products are probably well accustomed to change – significant and fast paced change at that. F5 are not a company to shy away from rapid change and replacing old technology and tools with newer, better ones. The change from the [...]

OpenFlow 1.0 Actual Use-Case: RTBH of DDoS Traffic While Keeping the Target Online

Tamihiro Yuzawa — Mon, 01 Apr 2013 13:55:01 +0000

Sakura Internet operates several data centers across Japan, including this one, and my team is in charge of building and taking care of our IP backbones. In this article, I will introduce the ongoing process of upgrading our DDoS mitigation solution, which happens to be a down-to-earth, if not widely applicable, use case for OpenFlow. [...]

A Small Yellow Wooden Door: Thinking Practically About SDN

Steven Iveson — Thu, 28 Mar 2013 08:00:51 +0000

As I do most days, I took a walk in the woods at the back of my garden after a hearty dinner. I was quite surprised to come across a small wooden yellow door I’d never seen before, set into the trunk of a tree I’d never noticed until today. I opened the door and squeezed [...]

Handling Tech Support Interaction Effectively

Ethan Banks — Wed, 27 Mar 2013 13:45:40 +0000

Network engineers deal with technical support frequently. That’s the nature of the networking business: the products often don’t work as advertised or break down under their own complexity. Throw in some ambiguous documentation that leaves you scratching your head, and you’ll finally resort to opening a case with the vendor to resolve the issue. In [...]

The Man in the White Suit

Steven Iveson — Mon, 25 Mar 2013 00:45:41 +0000

I know this is a technical blog, but I’ve always agreed with those that believe the best way to deliver a message is through a story. As imaginative and creative as I feel I can sometimes be, writing fiction just isn’t one of my strong points. So, rather than tell you an original story of my own I’m going to relate [...]

When Am I Going to Use This?

Keith Tokash — Sat, 23 Mar 2013 21:01:05 +0000

I imagine that prior to the industrial revolution, people didn’t struggle with niche skillsets that didn’t transfer. They didn’t need to wonder if they were spending countless hours learning something with no particular use outside their current job, listen to well-meaning friends and spouses assure them they’re worrying about nothing, only to face a layoff [...]

Firewalls: Expensive, Broken Routers

Neil Anderson — Fri, 22 Mar 2013 13:55:56 +0000

In a previous post on IPS, I made a fairly negative comment on the value that you get from enterprise firewalls in the modern environment. At the time, I said that I was just going leave that comment hanging and see what happened. Well, precisely no one challenged me on it, which means either everybody [...]

Using IP SLA Delay Feature to Safely Monitor Lossy Links

Charles Galler — Fri, 22 Mar 2013 13:31:08 +0000

IP SLA is a great feature if you want to add some automation and intelligence into the network. SLA is no SDN/OpenFlow, but it can be very useful. It can also take down a network. Let’s say you are using DMVPN for a number of spoke locations in your network. You have a primary Internet [...]

Surprised by Spam

Russ White — Wed, 20 Mar 2013 10:56:54 +0000

I attended my first in person meeting of the ISOC Advisory Council this last week — I’m a newly minted co-chair, and already haven’t been participating as much as I should (just like I don’t blog here as much as I should, a situation I’m undertaking to resolve!). We had a long discussion on the [...]

Six Things About F5 BIGIP V11 iApps

Ethan Banks — Mon, 18 Mar 2013 21:56:55 +0000

F5 Networks’ Local Traffic Manager (LTM) is my load balancer – okay, Application Delivery Controller, if you insist – of choice. The LTM platform is as feature-rich and well-supported as they come, with all sorts of customizability as well as the iRule scripting language (a superset of TCL) that lets you do fancy transaction manipulation. [...]

What’s Next for OpenFlow and Open Source?

Bill Owens — Thu, 14 Mar 2013 13:03:16 +0000

One year ago, the Open Networking Foundation was setting a blistering pace of standards development. Though their process is closed to outsiders, word had leaked out that not only were they on track to produce version 1.3 of the OpenFlow standard, but 1.4 would follow before the end of 2012. At some point that plan [...]

Tough Questions to Ask Network Vendors When Evaluating Products

John Harrington — Wed, 13 Mar 2013 13:47:01 +0000

Introduction In my previous post, I proposed investing in careful planning to extract the maximum value from your vendor meeting. But what happens when the presentation begins? In this post, I’ll outline a few high-level questions and lots of in-depth questions to help you get a better understanding of the ‘real’ product that’s being sold. High-level [...]

Vendor Certifications: A Career Jump Starter

Joey Lucero — Tue, 12 Mar 2013 03:18:57 +0000

“…I’d love to share how certifications have propelled me into a mid-level networking position. I can share my own personality, thoughts, and views on the subject… as long as I’m doing self-study. I don’t like having a teacher and same goes with a job, I personally really enjoy being my own technical lead, which I [...]

Webinar – Anuta Networks Demonstrates nCloudX – Register Now

Ethan Banks — Tue, 12 Mar 2013 00:14:21 +0000

This past January, Anuta Networks came out of stealth at Cisco Live in London, showing off their nCloudX platform, an SDN controller aimed at multitenant cloud providers. Anuta’s nCloudX controller can manage hardware common to many networks. As such, Anuta isn’t forcing providers to install OpenFlow switches, build a tunnel fabric, or otherwise disrupt their production environments [...]

Extracting the Most Value From Network Vendor Presentations

John Harrington — Tue, 05 Mar 2013 18:53:34 +0000

Vendors love nothing more than getting in front of their customers and talking about their products. You’ll always learn something from a presentation, but mostly they are an exercise in death-by-powerpoint. In this post, I’ll provide some some tips on getting the most from your time in these presentations. Vendor presentations can be really informative [...]

Why Would a Vendor Care About Network Field Day Events?

Ethan Banks — Tue, 05 Mar 2013 03:19:15 +0000

I’m in San Jose, California as a member of the Network Field Day 5 delegation this week. NFD is under the Tech Field Day umbrella of events, and is not a Packet Pushers event as such – although we’ve been a part of them, and Greg in particular has helped to organize some of them. [...]

My First Junos Switch: Detailed Review After Three Days Under the Covers

Paul Gear — Mon, 25 Feb 2013 02:19:37 +0000

Background This post is the story of my first practical look at Junos on Juniper EX-series switches. One day last December, Skeeve Stevens from eintellego opened a can of worms by offering a deal on Juniper equipment to all network engineers on the AusNOG mailing list. I had been looking for an excuse to try [...]

Thoughts on Working as a Consultant for a VAR

Ethan Banks — Mon, 25 Feb 2013 01:36:01 +0000

One of the questions I’m frequently asked via e-mail is how to get started in networking and/or whether or not a particular job change is a good idea. Those are always hard questions to answer intelligently because everyone’s individual situation is different. In addition, everyone’s personality is different. Different jobs work for different people. It [...]

NetCitadel and Software Defined Security

Neil Anderson — Thu, 21 Feb 2013 13:44:08 +0000

It’s been an exciting couple of weeks in the security realm, with a number of innovative startups appearing. That’s refreshing because recently most “innovation” in the security space has been something involving a new way of marketing a signature or reputation based system – and that’s just a bit rubbish, and not a little tiresome. Most [...]

Pull My Strings, I’m Your Puppet: Juniper Bringing DevOps to Networking

Anthony Burke — Thu, 21 Feb 2013 13:33:33 +0000

The buzzword in the industry of late is DevOps. It is one that I hope isn’t tarnished by the marketing machine where buzzwords go to die. DevOps is the shift in the paradigm of network and infrastructure management. Centralized infrastructure that is transparent to the administrator and end-user, IaaS, cloud – whatever you want to [...]

On Working Yourself to Death

Ethan Banks — Fri, 15 Feb 2013 21:34:50 +0000

In America, working a lot of hours is considered normal. Indeed, people who clock out promptly at the end of the day might be looked at askance, as if they aren’t giving enough of their heart and soul to the company. Over the years, I’ve tended to be one of those who works as long [...]

2e2: The Hindenburg of Cloud Providers & What It Means for Outsourcing

Glen Kemp — Thu, 14 Feb 2013 19:34:35 +0000

I have a somewhat love/hate relationship with cloud services and outsource providers. In my day job, we provide a few cloud services, resell a couple more, and use a handful to support some backoffice systems. Some services make complete sense to outsource, to the point you wonder why anyone ever bothered to do it for [...]

Benefits & Limitations of SPAN Ports

Darragh Delaney — Thu, 14 Feb 2013 18:25:02 +0000

A mirror or SPAN (switch port analyzer) port can be a very useful resource if used in the correct way. SPAN ports are typically found on network switch gear and the feature is used to send a copy of network packets seen on one switch port (or an entire VLAN) to another switch port. A [...]

Cisco ASA: High CPU in Dispatch Unit

Ethan Banks — Tue, 12 Feb 2013 22:51:59 +0000

I ran into an issue of unexpectedly high CPU utilization on a Cisco ASA firewall running 8.4.x family code; the CPU was running greater than 90%, when less than 25% was normal. The culprit was the “Dispatch Unit”; a little googling suggests that the ASA dispatch unit is the process through which the majority of [...]

Stuff You Don’t Need to Know: In Response to Ethan

Russ White — Tue, 12 Feb 2013 19:00:13 +0000

I would have put this in the comments to Ethan’s post –but responding post to post is much more fun. To begin, I must say I’m generally in agreement with Ethan’s main points on certifications and their ills –yes, you do have to maintain the cert. Yes, certifications tend to be one mechanism to drive [...]

Night of the Living Zombie Recruiter

Mrs. Y — Sun, 10 Feb 2013 19:29:27 +0000

Everyone in the IT industry has had to deal with the dreaded recruiter at some point in his or her career. You post your resume on Monster, Dice or one of the other job posting web sites out there and in less than 24 hours, there’s a deluge of email and/or calls from every recruiter under [...]

Bash Script to Gather All Your Cisco Serial Numbers via SNMP

Eric Flores — Sun, 10 Feb 2013 19:19:46 +0000

Recently, I was doing a true up of our Cisco SmartNet contract, and had to get the serial numbers from all of the Cisco devices on the network. Rather than access each device manually, I wrote a bash script that would get the serial numbers via the SNMP ENTITY table. To use the script, you [...]

Book Review: How to Master CCNP Route

Garry Baker — Sun, 10 Feb 2013 18:03:03 +0000

Book Details How to Master CCNP Route Rene Molenaar EBook PDF via instant download with watermark http://gns3vault.com Author Rene Molenaar is a Cisco Certified System Instructor (CCSI) and the creator of the site gns3vault.com which provides free Cisco labs for CCNA, CCNP and CCIE R&S based on the GNS3 emulator. Summary This book [...]

5 Tips for Escaping Troubleshooting Hell

Neil Anderson — Sun, 10 Feb 2013 17:47:41 +0000

We’ve all been there: it’s 5am and you’re up to your humerus in a network failure that no amount of coffee and swearing seems to fix. People are hovering on your shoulder, presumably to observe the ferocious look of concentration on your face. How do you escape this 3rd Circle of Troubleshooting Hell and ride [...]

Network Documentation Best Practices: What’s Important & How to Track It

Charles Galler — Thu, 07 Feb 2013 16:06:34 +0000

As a consultant, I have done several network assessments for clients. One of the biggest items that is almost always missing is documentation. In my assessment reports, I can’t just say, “You are missing documentation,” and leave it at that. I have to be more specific. I have to specifically call out what should have [...]

How to Build an IPSec VPN With Cisco ASAs & Overlapping Address Space

Eric Flores — Wed, 06 Feb 2013 19:30:20 +0000

There are times your company will partner with another to provide a resource to them. Often, this interaction is secured with a LAN-to-LAN (L2L) VPN tunnel. Most Cisco documentation about L2L VPNs are written for VPNs within the same organization, as opposed to different companies trying to peer with each other. L2L VPN tunnels within the same organization are [...]

Thoughts on Open EIGRP

Russ White — Mon, 04 Feb 2013 19:12:54 +0000

I’ve been in a hole working on a lot of other projects for a few months (hence my lack of posts!), but not so deep as to not notice that EIGRP has stated they will release a basic version of EIGRP, along with the intellectual property needed to implement that basic version of EIGRP. There [...]

OpenFlow Switching Performance: Not All TCAM Is Created Equal

Bill Owens — Fri, 01 Feb 2013 08:30:06 +0000

The fundamental promise of OpenFlow – that any switches and any controllers can be used to build a network – was perhaps always a fantasy. Every protocol definition has corner cases unanticipated by its authors; OpenFlow is no exception. And to make it implementable across as wide a range of hardware and software systems as [...]

Why Is Cisco Bothering With “Open” EIGRP?

Anthony Burke — Thu, 31 Jan 2013 13:34:53 +0000

My first taste of networking came via the Cisco Learning Academy. I did my CCNA and the old school ROUTE, and it did a pretty good job of praising the joys of EIGRP. You learned EIGRP early on, and it was always made to sound superior. The skills tests and all the labs revolved around [...]

The Dark Side of Vendor Certifications

Ethan Banks — Thu, 31 Jan 2013 02:49:29 +0000

Seen by many as the way to advance one’s career, vendor certifications are pursued by many eager networking professionals. I have done this myself over the years, having held certs sponsored by a variety of different vendors. I must concede that certifications have been helpful to me, but reflecting on certs yet again as I ponder the [...]

Network Visibility for Flexible Security Architectures

Neil Anderson — Wed, 30 Jan 2013 14:54:12 +0000

Inline security appliances are a fact of modern network security architectures. There are a number of compliance drivers to deliver inline protection for traffic in a number of zones within the network, which can be a real pain for the network admins and architects. Even passive tools such as IDS and packet capture sessions can [...]

Rationalizing the Case Against Internet Censorship

Umair Hoodbhoy — Tue, 29 Jan 2013 18:00:45 +0000

On September 17, 2012, the government of Pakistan banned YouTube access throughout the country. An anti-Islam video that had been deemed blasphemous was the cause of immense anger in the country, so the government blocked YouTube. The official reason given is that it was conducting its moral duty of protecting its citizens from offensive content. [...]

Understanding Crossbar Fabrics & The iSLIP Algorithm

Ethan Banks — Sun, 27 Jan 2013 20:40:16 +0000

Reading through a Cisco paper on the Nexus 5548P switch architecture, I came across the term iSLIP. “The [Unified Crossbar Fabric] is a single-stage high-performance 100-by-100 crossbar with an integrated scheduler. The scheduler coordinates the use of the crossbar between inputs and outputs, allowing a contention-free match between I/O pairs. The scheduling algorithm is based on an enhanced [...]

Using SSL Intercept With ADCs + Firewalls to Inspect & Clean Encrypted Traffic

Michael Schipp — Sat, 26 Jan 2013 23:22:42 +0000

The Problem Let’s take a typical enterprise. We have our internet connection going to our router (or ISP’s router), then handed off to our firewalls. We then break out to our internal and DMZ networks. Pretty standard stuff. We have our perimeter security controls sitting on the firewalls with a nice rule of “allow TCP [...]

15 Reasons You’re Technical Documentation Sucks

Glen Kemp — Fri, 25 Jan 2013 01:54:24 +0000

As part of my day job I produce technical documents, proposals and RFP responses for a (mostly) non-technical audience. I read and review even more of the above from sub-contractors, professional services consultants and technical support. I’m as likely to split an infinitive as the next person, but there is stuff I see on a [...]

Extending Layer 2 Across Layer 3 With L2TPv3 Pseudo-Wires

Brandon Roberson — Tue, 22 Jan 2013 13:58:43 +0000

Imagine one day your boss comes to you wanting to provide Internet access for a tenant in a distant building location that your organization has a presence (WAN connectivity) at. You think for a moment how to accomplish this task while keeping the following points in mind. How can we do this… securely, across a [...]

Security Superstition

Mrs. Y — Sun, 20 Jan 2013 21:36:20 +0000

A scientist is never certain. We all know that. We know that all our statements are approximate statements with different degrees of certainty; that when a statement is made, the question is not whether it is true or false but rather how likely it is to be true or false. – Richard P. Feynman Recently [...]

Five Things About Mentoring

Ethan Banks — Sat, 19 Jan 2013 18:23:15 +0000

In network engineering, a great opportunity is to be able to mentor someone else. Mentoring is that art of teaching someone else what you know. In that knowledge sharing, you help that person become a better network engineer. Or you teach someone who isn’t a network engineer something about networking. At least, that’s the general [...]

IOS CLI Speed Tips

Alex Clark — Mon, 14 Jan 2013 17:19:49 +0000

While studying for the CCIE, one point I hear all the time is the importance of being fast. With the new Troubleshooting section, speed is more important now than ever. With that in mind, I have compiled a small list of tips and methods to help you be as efficient with the IOS CLI as [...]

Cisco CCIE 350-001 v4 Written Exam Impressions

Ethan Banks — Fri, 11 Jan 2013 13:00:52 +0000

I took Cisco CCIE R&S written exam 350-001 version 4 today. This was one of my options to complete CCIE recertification. This is the second time I took v4 of this exam. The first time I took it in June 2012 at CLUS. I didn’t study at all, but since an exam is included in [...]

Why I Am Excited About OpenFlow

Ryan Niemes — Thu, 10 Jan 2013 13:00:27 +0000

I will admit that the first time I heard about OpenFlow I thought, “Great. Here’s another vaporware technology that will go nowhere.” I also realize that a lot of network engineers are saying the same thing, or might have difficulty understanding what the fuss is all about. If this is your thought, I hope that [...]

Take Pride in Your Work

Keith Miller — Tue, 08 Jan 2013 13:00:57 +0000

I was laying in bed Christmas night watching “Holmes on Homes” on the DIY channel, and something bothered me. I had a thought that just would not go away, so I decided to write about it. For those of you unfamiliar with the show, Mike Holmes is a Canadian general contractor who visits homes where [...]

How to Draw Clear L3 Logical Network Diagrams

Jaakko Rautanen — Mon, 07 Jan 2013 13:00:01 +0000

The biggest single problem I’m seeing when working on enterprise networks is the lack of L3 logical network diagrams. Most of the time I’m facing situations where a customer doesn’t have any logical network diagrams to give. L3 diagrams are vital for troubleshooting or for planning changes. Also, logical diagrams are in many cases more valuable than [...]

An Existential Crisis in My CCIE Study?

Matthew Mengel — Sat, 05 Jan 2013 13:00:02 +0000

When I was about three quarters of the way through writing my Master’s thesis, I was having some real doubts about whether the study I had undertaken had any value or purpose. In particular, I wondered whether the magnetic field images and starspot maps I was producing were real, or just mathematical artifacts generated by [...]

The Cost of IPv6 on Amazon Web Services

Jeff Loughridge — Fri, 04 Jan 2013 13:00:08 +0000

AWS is a great platform for businesses that have the technical savvy to administer servers and applications but do not want to bear the costs and responsibilities of on-site physical infrastructure. What AWS’s engineers have accomplished is very impressive. Given this achievement, I am surprised that several IaaS competitors have beaten AWS in rolling out [...]

IP Address Management for Today’s Complex Network Infrastructures

Sponsored Blog Posts — Thu, 03 Jan 2013 14:11:05 +0000

This blog post is sponsored by SolarWinds and written by Amy Pace, SolarWinds Product Marketing Manager. We live in a networked world. Nearly every company today, large or small, relies on TCP/IP networking to function—from basic services like email, file storage, and printing, to business-critical applications like e-commerce, customer relations, and supply chain management—and IP [...]

The End of Year Audit: Things Worth Checking While You Have a Minute

Ethan Banks — Thu, 20 Dec 2012 07:00:23 +0000

It’s the holiday season, and the screams of GET IT DONE NOW are gently muted, replaced with the quiet sounds of people gone on vacation and leaving you the heck alone. What better time to do some of that network clean up you’ve been putting off? Let’s make a list of fun things to check. [...]

OpenStack Quantum Network Implementation in Linux

Will Dennis — Wed, 19 Dec 2012 07:00:24 +0000

So there I was, a shiny new OpenStack Folsom install (via DevStack) on a single server, and everything seems to be working — except I can’t reach the darn VMs I’ve spawned! I had a vague idea of the network topology the installer had created (driven by the choice to use the new Quantum networking [...]

Multicasting Apple’s Bonjour Protocol

Brandon Roberson — Tue, 18 Dec 2012 08:00:28 +0000

Let’s face it. Apple’s Bonjour protocol is likely here to stay, or at-least for the foreseeable future until Apple decides otherwise. If you have an Apple device and wish to do printing or require the use of its discovery services, you will very likely encounter Apple’s Bonjour protocol. I will spare the many technical details [...]

Using CBQoS and NetFlow to Solve Network Traffic Problems

Sponsored Blog Posts — Mon, 17 Dec 2012 13:50:25 +0000

This sponsored blog post is written by Patrick Hubbard, SolarWinds Head Geek. Admit it – you have a problem. A bandwidth problem. It’s probably worst on WAN links at about 10am Tuesday mornings, when VoIP MOS score monitors turn orange, tickets start coming in about slow Exchange access and an exec calls in to say [...]

Interacting With the Cisco ASA CLI Using the HTTPS Interface

iggdawg — Wed, 05 Dec 2012 14:02:50 +0000

Most people are familiar with interacting with the ASA over HTTPS to get captures off the box, but every CLI mode is available using a browser. There are a lot of handy practical situations where you’d want to do this, including simply avoiding using a steaming pile of Java. Below is the simplest way to [...]

12 Tips for Effective IPS Deployment (Goats Optional)

Neil Anderson — Tue, 04 Dec 2012 13:51:38 +0000

Fresh from a conversation so frustrating that I could have cheerfully punched a goat today, I thought I’d jot down my thoughts on intrusion prevention systems (IPS) and how to effectively deploy it. I would have written a post on how not to deploy it, but that would have meant breaking an NDA. IPS is a vital [...]

Reminder: Big Switch SDN & OpenFlow Webinar on Thursday

Greg Ferro — Mon, 03 Dec 2012 19:36:47 +0000

This Thursday at 1000PST/1300EST/1800UTC is the Big Switch webinar on their recent launch of Big Virtual Switch SDN applications and controller. Join us for the event and demo…..

Sign up for the Webinar

Ode to a Network Engineer (in the Style of Bukowski)*

Mrs. Y — Thu, 29 Nov 2012 17:22:00 +0000

You are not a technical sink. You are not an infant made to passively suck up the pabulum from a vendor. Do your homework. Study. Learn. Improve yourself. It’s what an engineer is supposed to do. Don’t expect your employer to do it for you. Don’t expect applause. Your professional life is your responsibility. Unless [...]

Holiday Greetings Podcast – Your Audio Greeting Cards Wanted!

Ethan Banks — Wed, 28 Nov 2012 15:14:36 +0000

For the community show we plan to release during the last week of December, we’d like to include a montage of audio “greeting cards” from all of you. Everyone is invited to participate (yes, vendors too, as you’re a huge part of the community). The process is simple. Record your greeting in any audio format [...]

Mind Over Matter: The Subconscious CCIE

Nick Allgood — Tue, 27 Nov 2012 13:58:41 +0000

I recently passed my CCIE Routing and Switching on my 2nd attempt about a week ago, four months after my first attempt. In that four-month gap, I spent a lot of time on my mental, emotional, and spiritual growth that I feel strongly contributed to my success. The two minds You will find a lot [...]

Why Network Engineers Are Sick of SDN – And What Vendors Can Do About It

Ethan Banks — Sat, 24 Nov 2012 18:56:24 +0000

2012′s dominant networking buzzword has been SDN: software defined networking. Packet Pushers has talked about SDN quite a bit because it represents a re-thinking of the way that the industry has built networks for the last two decades. SDN as a concept is both technically interesting and creatively inspiring, giving many pause for thought and [...]

Simple Perl Script to Produce a Configuration From a Template

InfiniteMonkey — Thu, 22 Nov 2012 07:00:11 +0000

Everyone has their own method of leveraging configuration templates. Engineers utilize Network Management Systems, text files with find & replace functionality, and homegrown scripts. There are even some deranged individuals that use word processor form letter / mail merge functionality. Personally, I tend to use the Perl script that I’m about to share with you. [...]

The Scorched Earth LAN & A Better Enterprise Security Model

Neil Anderson — Wed, 21 Nov 2012 18:46:45 +0000

The enterprise LAN is a blasted wasteland of dead and dying technologies. I call for a strategic retreat. It seems to me that endpoints, such as desktops, and the LAN in enterprise networks just aren’t defensible any more. Not only are we still relying on signature based controls on the endpoint and in the network, [...]

Riverbed Steelhead and Juniper WX Part II – When a Tunnel Is Not a Tunnel

Glen Kemp — Wed, 21 Nov 2012 18:27:36 +0000

In my previous post “Getting Nerdy about WAN optimisation“, I discussed some of the basics of WAN optimisation and how the Juniper WX and Riverbed Steelhead capture traffic. Now I’d like to get into the detail on how they shift traffic between networks. Once traffic enters either appliance, there are differences on how the traffic [...]

VoIP Call Playback & Other Wireshark Voice Tools

Matthew Mengel — Tue, 20 Nov 2012 14:33:53 +0000

I am not a Voice Engineer. Like many, though, I’ve found it inevitable that pure packet herding will intersect with voice at some point. A couple of weeks ago, we upgraded our existing office PBX. The upgraded system has IP telephony capability, and this was important as we are expanding our services on the main [...]

Cisco Configuration Archive & Rollback: Using ‘Revert’ Instead of ‘Reload’

Charles Galler — Mon, 19 Nov 2012 07:00:49 +0000

I wrote an earlier blog article about using the reload command. The reload command used to be the only tool to recover from configuration errors when working on a device remotely. You would save your configuration and issue the ‘reload in’ command, giving yourself enough time to make your changes. If you finished in time [...]

Preparation Lessons Learned From a Freshly Minted CCIE

ddib — Sat, 17 Nov 2012 01:42:11 +0000

I recently became a CCIE, and I want to share some lessons learned during my 2 years of studying. I will not describe in detail what topics to study, but I will describe some valuable lessons I learned during my studies. My hope is that this will help someone in their journey because I am [...]