Networking Primer – Part 3: Application, Presentation and Session Layers

Previous: Networking Primer – Part 2: Defining Networking with OSI and TCP/IP Suite

I’ve decided to group the top three layers together into one post. This is because these are more related to the data to be transmitted across the network, rather than the underlying transport mechanisms themselves. These three layers deal with the semantics of the communication, such as who the data will be sent to, the format of the data and the etiquette to be adhered too between the communicating nodes.

Lego Pirate Ship

The Pirate Ship: As with most technical concepts, analogies can help us understand the underpinning processes which are happening as part of the communication. For this series, I’m going to use the following analogy: I work in an office in Manchester and I’d like to send a pirate ship made of Lego to a friend, Rich, who works in an office in […]

Networking Primer – Part 2: Defining Networking with OSI and TCP/IP Suite

Previous: Networking Primer – Part 1: Introduction

What is a network?

This may sound like a very basic question, but I’ll assume the lowest common denominator here and define this briefly.

A network is set of two or more computing entities (nodes) that are configured to communicate with each other by passing information across an interconnecting media.

Ok, now we got that out of the way, we can talk about how exactly those nodes communicate with each other in a way that makes sense and achieves our objective of passing information between them.

A Little History

It is easy to imagine how the first baby steps of networking which occurred in the mid-20th century. As with all technology we start with the simplest goal and see how we can use what tools we available to use to achieve that goal. I’m not going to go into sending signals down telegraph wires, etc. but […]

Networking Primer – Part 1: Introduction

The world of networking has been fairly static for many years now. It’s been historically characterised by static infrastructures that require infrequent changes. These configuration changes were performed via command line interfaces by network engineers, usually sitting with a laptop and a cable plugged directly into a piece of networking hardware. Activities were manual, repeated for every individual device and extremely error prone due to the non-human readable nature of network configuration information.

The workloads running in the modern datacenter have most definitely changed in recent years. It has become apparent that the capabilities of current networking devices and operational approaches simply cannot keep up with the pace of change. In the modern datacenter, the rapid and overwhelming success of server virtualisation has fundamentally changed the way applications consume resources and the network has become somewhat of a bottleneck in providing agile, reliable and cost effective means of […]

Software Defined X – Automation: Job Stealer or Job Enabler?

I’ve had many conversations in recent weeks about the commoditization of the data center with many being concerned about the effect of the diminishing need for specialist hardware and greater automation through software. More specifically, how that might affect the job prospects of administrators and other technical roles in the modern IT environment.

We are in an era of rapid evolutionary change and this can be unsettling for many as change often is. There seems to be a wide variety of reactions to these changes. At one end there is the complete denial and a desire to retain the status quo, with an expectation that these industry changes may never occur. In the middle, we have those that tip their hat in recognition of the general direction of the trends, but expect things to happen more gradually and then there are those that embrace it with an expectation of gaining some […]

Whitepaper: Command Email – A New Military Message

It’s been a few months since my last blog. As always work commitments come first and it’s been a bumper couple of months. I’ve been studying the military messaging environment and how it is evolving and summarized my findings in this whitepaper. The main thrust is that organisations should be considering moving away from traditional Military Message Handling Systems (MMHS) approaches in favour of lighter, simpler, COTS based, modular and more cost-effective solutions.

“ The secret of war lies in the communications”

Napoleon Bonaparte

  The ability to communicate effectively and without ambiguity has been, and continues to be, instrumental to the success of military organisations across the world. Throughout history military organisations have pushed the boundaries of communication. Military messaging has evolved from smoke signals, to written letters, to telegraphs, to radio, to email and to unified communications today. Sending messages between organisations, units, roles and individuals is paramount to […]

Google Sniff-View Cars?

Probably one of the more interesting news stories this month is the revelation of Google admitting that it packet sniffed on unsecured public Wi-fi networks. Read news here.

It appears that Google Street View cars were driving around taking pictures of various locations, but were also kitted out with network sniffers that could connect to unsecured public wi-fi access points, monitor and record data transmissions across those networks. Naughty stuff Google. This went on for a total of 3 years and accordingly to Google the activity was a “simple mistake”. This continues to re-affirm beliefs that public Wi-fi networks are serious security risks for both individuals and companies. If one of the world’s largest IT monopolies can do this by accident, cough, what could a determined plan of attack achieve.

So how did they do it? The answer is, without rocket science. It’s easy enough to connect a laptop […]

How secure is my wireless network? Four Tips to bump up security.

Do you think your wireless network is secure?

If the answer is yes. The BackTrack (BackTrack 4 – www.backtrack-linux.org) pentration testing OS would beg to differ.

BackTrack 4 manifests itself in an entirely customised distribution of Linux. The underlying Linux distro is Ubuntu, but has been specifically enhanced, configured and packaged for the purposes of penetration testing. Within the package you receive a wide variety of wireless cracking, network scanning and password breaking tools.

There are several options you can select for running BackTrack to start your activities. You can install it as an OS on your harddrive, you can install it and run it from a USB stick and you can even run the entire OS from CD. The latter option requires no installation at all. You simply select a machine, boot from the CD and then remove the CD when finished. I chose the latter option for […]