Welcome to Fabio’s Tech Corner

This website is about those technical activities that require a planning and training process I really enjoy doing, such as:
– building robust, complex and secure networks;
– Technical diving and dive risk management;
– Activities connected to flying.
The posts are organized in Topics and indexed in the Topics Index page.

Seagull Jonathan

Flying

I was an IT guy with the love for flying: I could legally fly a plane before driving a car and before then I was hacking the firmware of a Commodore 64, but IT wouldn’t pay for flying so I switched hobby with work: flying for a living and IT as a hobby. What remained a constant in all of this was my love for the Sea and diving. That is the main reason the icon on the page is a Seagull. I am still in love with these three activities and, in the case of IT, especially with the background networking bits: Routers, Switches, Access Servers and the mechanics to make all of this working. Your Comments are welcome to improve the site and develop topics of interest. Thank you for visiting.

Advanced Routers in SOHO environment

This article will illustrate the rationale behind deploying a user selected (and specifically a Cisco) router, notwithstanding cost and complexity, in a home/small office environment. Many people will rely on the ISP provided router to connect to the Internet. This router is often included in the price of the connection, ISP maintained and often when/if it breaks is replaced for free by the ISP.
Given all the advantages, why would you be willing to spend a substantial amount of money to buy a router and why would you decide to buy a complex, expensive (compared to other ‚Äúconsumer grade”) routers? (more…)

Select VPN Traffic for Cisco EZVPN

The EZVPN configuration used in the previous article forwards all incoming traffic on the VPN inside interface out to the VPN tunnel. This might be less than ideal, but discussing with Cisco TAC I found out that there is no way around it. In this article I will show how to use a second router to avoid this (more…)

Configure Witopia VPN on Cisco

This post is part of the VPN series and it will show how to connect a Cisco IOS device using the EZVPN feature to a Witopia IPSEC gateway
When I left the States it was difficult to make do without accessing a series of services that had been available while connected to the Internet there. When you wish to use those services with a computer the solution is simple: load a VPN client and connect.Doing it with a Wii or an Apple TV is a bit more complex: (more…)

VPN – Why? What? How?

In this series of posts I will show how to use IPSEC technology and VPN to secure data when roaming in public access hotspots with your mobile devices and then how to implement your own VPN server or connect your home network so some traffic will be forwarded to the VPN and the rest will be forwarded through your ISP network. This post will introduce the VPN basic concepts.

Protecting your data with VPN technology

A few days ago I went with my son to a 5 team water-polo tournament (by the way his team won all 4 of their matches :-)) and at the swimming pool there was an open hotspot, no password no security. (more…)

Your Data in a Connected World

In this post I will lay the ground explaining the need to deploy VPN and some considerations about the so-called cloud services and implies trusting them with your data

Data Transport Issues

We expect our data to be always available wherever we are. Most of the time data is not physically on our device: it will have to transit across a network connecting our device (more…)

Create cfg file for your YubiRadius DomU

In this post which is part of the series on how to import YubiRadius, a Free Radius appliance implementing OTP validation, into Xen Open source Hypervisor, we will finally create the .cfg file needed by the Hypervisor to create the virtual machine and boot it

As we saw earlier most of the work is already been done by the Xen.tools, which would already have created the cfg file (more…)

Modify Yubiradius image to boot in Xen

In this post which is part of the series on how to import YubiRadius, a Free Radius appliance implementing OTP validation, into Xen Open source Hypervisor, we will modify the image we have built in order to have all the bits and pieces to correctly boot under Xen Hypervisor environment as a paravirtual domain
The image we created in the previous post would not boot as a Xen paravirtual host, but it would (eventually) boot in a fully virtualized domain. It would be extremely inefficient (more…)

Build the Xen usable .img file

In this post which is part of the series on how to import YubiRadius, a Free Radius appliance implementing OTP validation, into Xen Open source Hypervisor, we will build an .img file containing a filesystem, mount it and then copy the Virtual Appliance files into it
The first step consist in creating a file of the proper size with

dd if=/dev/zero of=/workdir/empty.img bs=516096c count=#cyl

This statement sets (more…)