Welcome to Dutch-Fi’s homepage! The blogs on this site will primarily be IT related, with a heavy emphasis om Security and Wireless.


Cisco Champion 2018

The Cisco Champions for 2018 have been announced and I am honored and proud to be able to announce that I have been selected. A special thanks goes to Pieter-Jan Nefkens (Twitter: @pjnef) for supporting and nominating me for this program. What actually is a ‘Cisco Champion’? Several vendors have a global advocacy programs. For …

Frame classes

While studying for the CWNA and CWAP, you learn about the 802.11 State Machine. This describes the states of client connectivity during a session. In the provided schematic there are three Frame classes mentioned.   Below an overview of these frame classes. Class 1 Control frames Acknowledgement (ACK) CF-End Clear to send (CTS) Contention-Free (CF)-End+ACK …

Maximum allowed transmission power in the ETSI domain

In most Wi-Fi related documents, especially in study books, you read about the regulatory maximum allowed transmission power (EIRP)  for access points. The values described are usually based on the standards as defined by the United States Federal Communications Commission (FCC). As a Dutch based Wi-Fi consultant these are not the values I can use as a standard for …


Hi, my name is Patrick Nefkens, also known as Dutch-Fi.

The original reason for starting this blog was because in my experience the phrase ‘This is something I will never forget again’ is just simply not true. So I started to write things down so I could look it up instead of trying, and often failing, to remember the specifics of a solution or the exact format of a hidden command.

Over the years I have found solutions to quirky bugs in and learned a lot from other blogs. The willingness of people to share their knowledge never ceases to amaze me and therefore I thought it was about time I shared some of my experiences in my own blog.

Many blogs are in the process of being translated from Dutch to English and have to be moved from my internal blogsite to this one. So it may take some time before everything is publicly available.

A homepage section

This is an example of a homepage section. Homepage sections can be any page other than the homepage itself, including the page that shows your latest blog posts.