WifiNigel

For the past few years, I've maintained a white paper on the use of the 5GHz spectrum for Wi-Fi networks here in the UK. As Wi-Fi text books tend to focus on the spectrum available in the USA, I put this document together to clarify how 5GHz spectrum may be used in the UK. Following the release of a Voluntary National Specification document by Ofcom in August 2017 ( VNS 2030/8/3 ), additional channels became available for use in the UK on 5GHz. As we now have additional spectrum, it's time for an update to my white paper to detail the new spectrum that is available. Prior to updating the white paper, I published a summary sheet that shows the new spectrum allocation. This can be obtained obtain from my previous blog article:  UK 5GHz WLAN Spectrum Allocation (August 2017)  (this is definitely one to print off and laminate). I have now completed my updates to the white paper, which I am pleased to share with you now. Note that in addition to adding the new spectrum det

I've been taking a look at Scapy as I've been learning more about Python. It's a great Python-based tool for capturing, analyzing and creating network packets. There are some great resources to learn more bout Scapy, and even some cheat sheets out there. But, as there were quite a few new concepts (for me) and my own interest is in Scapy for 802.11 related activities, I put together my own Scapy for 802.11 cheat sheet . You can grab a copy from here if it may be useful to you. References : Scapy 802.11 cheat sheet  Scapy docs: https://scapy.readthedocs.io/en/latest/ Building Network Tools With Scapy SANS Scapy Cheat Sheet

To address perceived privacy issues, some wireless clients adopt a randomized MAC address in probe frames when probing  for wireless networks. In this post  I take a quick look at how you might see clients using randomized MAC addresses.  Background When a wireless LAN client needs to find a nearby access point to join a Wi-Fi network, it has two choices: Passive scanning: a client will listen to beacon frames, broadcast by nearby access points, that advertise networks that it makes available. This can be quite a slow process, as a client cycles though channels and waits to hear beacons. Active scanning: a client will cycle through channels and send out probe frames to proactively query nearby APs for a specific wireless network (SSID). This will generally be a faster method of finding networks that the client is configured to join, and may be used by all clients in conjunction with passive scanning. One (unfortunate) side-effect of active scanning is that a client a