Masterclass – Tcpdump – Parameters

This Masterclass article series aimes to provide in-depth technical information on the installation, usage and operation of the classic and supremely popular tcpdump network traffic analysis program including alternatives, running tcpdump as a process, building expressions, understanding output and more. I’ve covered the Basics previously, will cover Parameters here, then filter Expressions and finally Interpreting Output. […]

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Steven Iveson

Steven Iveson

Steven Iveson, the last of four children of the seventies, was born in London and has never been too far from a shooting, bombing or riot. He's now grateful to live in a small town in East Yorkshire in the north east of England with his wife Sam and their four children.

He's worked in the IT industry for over 15 years in a variety of roles, predominantly in data centre environments. Working with switches and routers pretty much from the start he now also has a thirst for application delivery, SDN, virtualisation and related products and technologies. He's published a number of F5 Networks related books and is a regular contributor at DevCentral.

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The post Masterclass – Tcpdump – Parameters appeared first on Packet Pushers Podcast and was written by Steven Iveson.

PQ Show 26 – Cisco Live Network, IPv6 and Hugs All Round – Sponsored

Guests Patrick Warichet Alain Fiocco @alainfiocco Andrew Yourtchenko @ayourtch Kumar Reddy @kumarreddy Show Notes You can follow the Cisco IPv6 Lab Team on Twitter at @cisco6lab “Happy Eyeballs” – RFC6555 – Happy Eyeballs: Success with Dual-Stack Hosts – http://tools.ietf.org/html/rfc6555 Test your IPv6 http://test-ipv6.com/ IPvFoo – https://code.google.com/p/ipvfoo/ 6lab.cisco.com/stats Sessions on Cisco Live 365 from Orlando, 2013. […]

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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 PQ Show 26 – Cisco Live Network, IPv6 and Hugs All Round – Sponsored appeared first on Packet Pushers Podcast and was written by Greg Ferro.

Show 151 – Defining Software Defined Whatever

The hosts of the Speaking in Tech podcast join the Packet Pushers to discuss “not networking” just ahead of the Cisco Live conference. CLUS roving reporter Chris Wahl @chriswahl takes part in the melee. Dropping insults on ITIL and ITSM once again. Defining Software Defined Whatever because “My Other Software Defined is Your Mom” Software […]

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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 Show 151 – Defining Software Defined Whatever appeared first on Packet Pushers Podcast and was written by Greg Ferro.

Masterclass – Tcpdump – Basics

This Masterclass article series aimes to provide in-depth technical information on the installation, usage and operation of the classic and supremely popular tcpdump network traffic analysis program including alternatives, running tcpdump as a process, building expressions, understanding output and more. I’ll cover the Basics here and move on to Parameters, then filter Expressions and finally Interpreting […]

Author information

Steven Iveson

Steven Iveson

Steven Iveson, the last of four children of the seventies, was born in London and has never been too far from a shooting, bombing or riot. He's now grateful to live in a small town in East Yorkshire in the north east of England with his wife Sam and their four children.

He's worked in the IT industry for over 15 years in a variety of roles, predominantly in data centre environments. Working with switches and routers pretty much from the start he now also has a thirst for application delivery, SDN, virtualisation and related products and technologies. He's published a number of F5 Networks related books and is a regular contributor at DevCentral.

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The post Masterclass – Tcpdump – Basics appeared first on Packet Pushers Podcast and was written by Steven Iveson.

Speaker for the Dead – Telnet

The idea of this article series is for me to play the part of a ‘Speaker for the Dead’ for technology that has or is becoming ‘end of life’ or legacy and/or irrelevant (or which should be). In this article, I’ll cover Telnet; the good, the bad, the ugly, the full (but brief) and honest […]

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Steven Iveson

Steven Iveson

Steven Iveson, the last of four children of the seventies, was born in London and has never been too far from a shooting, bombing or riot. He's now grateful to live in a small town in East Yorkshire in the north east of England with his wife Sam and their four children.

He's worked in the IT industry for over 15 years in a variety of roles, predominantly in data centre environments. Working with switches and routers pretty much from the start he now also has a thirst for application delivery, SDN, virtualisation and related products and technologies. He's published a number of F5 Networks related books and is a regular contributor at DevCentral.

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The post Speaker for the Dead – Telnet appeared first on Packet Pushers Podcast and was written by Steven Iveson.

[CCIE] Spanning-Tree Part 1 – Nerd Knobs

I wrote this post not only to put out some information on one of the least-understood facets of networking (especially in data center, as most technology today is aimed at making STP irrelevant) but also to help get something on paper for me, seeing as I am going down the CCIE path full force now, and this has always been a weak area of mine. This post will assume you have CCNP-level knowledge about Spanning Tree Protocol (STP).

[CCIE] Spanning-Tree Part 1 – Nerd Knobs

I wrote this post not only to put out some information on one of the least-understood facets of networking (especially in data center, as most technology today is aimed at making STP irrelevant) but also to help get something on paper for me, seeing as I am going down the CCIE path full force now, and this has always been a weak area of mine. This post will assume you have CCNP-level knowledge about Spanning Tree Protocol (STP).

[CCIE] Spanning-Tree Part 1 – Nerd Knobs

I wrote this post not only to put out some information on one of the least-understood facets of networking (especially in data center, as most technology today is aimed at making STP irrelevant) but also to help get something on paper for me, seeing as I am going down the CCIE path full force now, and this has always been a weak area of mine. This post will assume you have CCNP-level knowledge about Spanning Tree Protocol (STP).

All Aboard the Application Train!

It’s been an interesting week so far… and it’s only Wednesday. In just a little over a day and a half, we’ve had hundreds of people stop by our booth at Cisco Live! and I wanted to share a few observations from those interactions:

  1. A significant number of people still do not know or understand much about SDN. This isn’t surprising and further underscores the disservice vendors have done at creating confusion that I wrote about a couple of weeks ago.
  2. When you talk about an application-centric approach to networking and network service automation, people get interested very fast, even when they are not building or using a cloud.
  3. Everyone is asking for examples of real use cases and deployments to help them determine which vendors they should engage/invest their time.

I suppose I shouldn’t be too surprised that networkers aren’t that familiar with software. Given that Cisco is talking a little more about software and software-defined networking these days, that’ll probably change by this time next year. In fact, Cisco spent much of Wednesday morning outlining its “vision” for application-centric infrastructure. From my perspective it’s a great thing to have Cisco promote the concept we’ve been pushing for a Continue reading

Speaker for the Dead – Spanning Tree Protocol

A friend of mine* text me early last week asking if I wanted to go to the cinema and watch the film After Earth. I couldn’t/wouldn’t go as I’m still up to my neck in book writing, but I thought I’d distract myself for a minute or two and read a few reviews of the […]

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Steven Iveson

Steven Iveson

Steven Iveson, the last of four children of the seventies, was born in London and has never been too far from a shooting, bombing or riot. He's now grateful to live in a small town in East Yorkshire in the north east of England with his wife Sam and their four children.

He's worked in the IT industry for over 15 years in a variety of roles, predominantly in data centre environments. Working with switches and routers pretty much from the start he now also has a thirst for application delivery, SDN, virtualisation and related products and technologies. He's published a number of F5 Networks related books and is a regular contributor at DevCentral.

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The post Speaker for the Dead – Spanning Tree Protocol appeared first on Packet Pushers Podcast and was written by Steven Iveson.

Networking Learning Paths – Route/Switch or Speciality Knowledge?

I spent the first ten years of my career in mobile telecoms. I learned a ton of lessons and I really enjoyed it, but I’ve always been drawn to networking. However I wasn’t getting hands-on exposure to data networks in my telco job so I had to teach myself. In 2002 I began the transition […]

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John Harrington

John is an experienced data center engineer with a background in mobile telecoms. He works as a network test engineer for a large cloud service provider, and is gradually accepting that he's a nerd. He blogs about network technology and careers at theNetworkSherpa.com. You can reach him on twitter at: @networksherpa

The post Networking Learning Paths – Route/Switch or Speciality Knowledge? appeared first on Packet Pushers Podcast and was written by John Harrington.

VIRL – Why you need to know about it!

At Cisco Live in Orlando I had the chance to demo the Virtual Internet Routing Lab (VIRL). It is Cisco’s answer to GNS3 or Junipers’ Junosphere using virtualization to create virtual network topologies. This tools will be as revolutionary as GNS3, but at a much larger scale. It is an awesome tool that can be used for certification studying but also to validate production designs. Everyone I spoke to couldn’t wait to get their hands on it, including me!

Below is a screen shot of VIRL. It is using Oracles VMMaestro GUI based on Java. In the screen you can see network topology which is drop and drag. On the left side in purple there is a list of all saved networks. The right middle side has a list of supported devices. Top right side has all of the currently running devices and bottom right preconfiguration tabs. To access CLI of these routers, you has to run in simulation mode then Telnet to individual devices. The preconfiguration is a nice feature that allows you preconfigure IP addresses, Loopback interfaces or routing protocols like OSPF or BGP.

Virtual Internet Routing Laboratory screen shot.

Virtual Internet Routing Laboratory screen shot.

VIRL supports virtualizing Cisco’s modified operations system. Cisco Continue reading

Regarding scale-out network virtualization in the enterprise data center

There's been quite a lot of discussion regarding the benefits of scale-out network virtualization.   In this blog I present some additional thoughts to ponder regarding the value of network virtualization in the enterprise DC.  As with any technology options, the question that enterprise network operators need to ask themselves regarding scale-out network virtualization is whether it is the right solution to the problems they need to address.

To know whether scale-out network virtualization in the enterprise DC is the answer to the problem, we need to understand the problem in a holistic sense.  Let's set aside our desire to recreate the networks of the past (vlans, subnets, etc, etc) in a new virtual space, and with an open mind ask ourselves some basic questions.

Clearly at a high level, enterprises wish to reduce costs and increase business agility.  To reduce costs it's pretty obvious that enterprises need to maximize asset utilization.   But what specific changes should enterprise IT bring about to maximize asset utilization and bring about safe business agility?  This question ought to be answered in the context of the full sum of changes to the IT model necessary to gain all the benefits of the scale-out Continue reading

How do I Justify this?

“Say I’m convinced that my company should choose one technology over another. How can I tell the whole truth, cover all the bases, explain all the alternatives, while making certain I make the case that the technology I’ve made, or would like to make, is the right one?” In case you’ve ever wondered what it’s […]

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Russ White

Principal Engineer at Ericsson

Russ White has scribbled a basket of books, penned a plethora of patents, written a raft of RFCs, taught a trencher of classes, nibbled and noodled at a lot of networks, and done a lot of other stuff you either already know about — or don't really care about. You can find Russ at 'net Work, the Internet Protocol Journal, and his author page on Amazon.
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The post How do I Justify this? appeared first on Packet Pushers Podcast and was written by Russ White.

DNS poisoned for LinkedIn. Affects us? Sure, it does.

linkedin

If you were unable to access LinkedIn for almost the entire day earlier this week, then you can take solace in the fact that you were not the only one, not able to. Almost half the world shared your misery where all attempts to access LinkedIn (and several other websites) went awry. This purportedly happened because  a bunch of hackers decided to poison the DNS entries for LinkedIn and some other well known websites (fidelity.com being another).

Before we delve into the sordid details of this particular incident lets quickly take a look at how DNS works.

Whenever we access linkedin.com, our computer must resolve this human-readable address “linkedin.com” into a computer-readable IP address like “216.52.242.86″ thats hosting this website. It does this by requesting a DNS server to return an IP address that can be used. The DNS server responds with one or more IP addresses with which you can reach linkedin.com. Your computer then connects to that IP address.

So where is this DNS server located that i just spoke about?

This DNS server lies with your Internet service provider, which caches information from other DNS servers.  The router that we have at home also Continue reading

Last 24

1. Went to Dubai International airport at 1 am local time
2. Stayed in Emirates business lounge, blogging to write about the recent Indonesian Networkers 17-19 June 2013 aka 100NGN Workshop in Jakarta
3. Got info there was delay for about an hour from the original 2.55 am local time
4. Continued blogging
5. At 3.30 am there was announcement the new schedule for the flight now is 6 am
6. Didn't want to sleep to avoid missing the flight, randomly browsing the Internet
7. Close to 6 am, no announcement about the boarding
8. Felt very sleepy so decided just to go to boarding gate around 6 am
9. Got into airplane around 6.30, flight finally took off at 7 am
10. Couldn't sleep during the 13.5 hours flight to JFK New York, watched lots of movies
11. Arrived 1.5 hours before my connecting flight
12. There was announcement from pilot, due to medical condition of one passenger all others must stayed inside airplane until the situation is cleared
13. Came out from airplane with only about an hour before the next flight to Orlando
14. Run to border security with Quick Connect paper Continue reading

PQ Show 25 – Cisco OTV Deep Dive Part 2

New voices gather in the Packet Pushers virtual boardroom for a discussion of Cisco’s layer 2 extension technology, Overlay Transport Virtualization (OTV). Ethan Banks hosts a recording of about two hours worth of content about OTV; this show is the second hour (well, almost another hour). Joining Ethan are first-time guests Jamie Caesar, Colby Glass and Ken Matlock. Jamie, Colby and Ken have […]

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Ethan Banks

Co-host at Packet Pushers

Ethan Banks, CCIE #20655, has been managing networks for higher ed, government, financials and high tech since 1995. Ethan co-hosts the Packet Pushers Podcast, which has seen over 3M downloads and reaches over 10K listeners. With whatever time is left, Ethan writes for fun & profit, studies for certifications, and enjoys science fiction. @ecbanks
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The post PQ Show 25 – Cisco OTV Deep Dive Part 2 appeared first on Packet Pushers Podcast and was written by Ethan Banks.

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