Troubleshooting a Broken Network Adapter in vSphere ESXi

You reboot a VM and 2 hours later you realise there’s no network connectivity on that VM.
You try to open theĀ Network and Sharing Center console but the window just hangs and everything seems to be chugging alongĀ very slowly.

I’ve experienced a number of different scenarios where network adapters go AWOL in a VM – usually caused by a guest (Windows Update) or VM hardware update. For the latter it is best practice to update the VMware Tools first before upgrading the hardware version.

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Got a WPS Enabled Router? Consider Disabling it or Risk DoS

WPS stands for wi-fi protected set-up. It’s supposed to make it easier for non-tech savvy people to authenticate devices on to a wireless network by pressing a physical button on the router or entering a PIN in to a device to make it known to the network.

The problem with WPS is quite a big one. There are many fundamental flaws in the WPS model – I won’t go through these in this article but a simple Google search will expose these many vulnerabilities in WPS – one which I discovered by accident today is a relatively (scarily) easy denial of service on an end-users network.

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How to Boost your Wireless Strength with DD-WRT

If you have a DD-WRT powered router then you already know how powerful and feature-full it is, compared to a standard out-of-the-box ISP provided router.

This article will be about making use of the features that DD-WRT provides out of the box, as well as some other ‘hacks’ we can use to boost the wireless signal in your home or office.
The ones I will talk about today are as follows (in order of usefulness and ease):

  1. Wireless channel selection
  2. Update firmware and/or drivers!
  3. Transmit (Tx) Power
  4. Beacon Interval

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Force DD-WRT to use OpenDNS Servers for DNS Queries

In one of my recent articles, I explained how I set-up a guest wireless network for our work place (after getting it to work with the right wireless channel :))

After configuring the guest access point, I set up the DNS servers to point to OpenDNS in order to provide a safer and faster DNS service (compared to the default DNS servers our ISP provides) as well as choosing what web-sites should be allowed on the network.
For example, bandwidth hogging (Media/Video Sharing) and other web-sites which could potentially be used for illicit purposes (P2P/File Sharing) are forbidden on the network.

However, without any firewall rules on the router itself, it would still be possible for a guest on the network to change their DNS settings on their wireless adapter to point to any other DNS server; effectively bypassing all OpenDNS filters on the network for that specific client.

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Choosing the Right Channel for Your Wireless Network

Choosing the wireless channel to use on your network can be a real pain in the ass; especially if you live or work (if this is a business network) in a densely populated area.

Put simply, channels are the radio ‘frequencies’ which your devices use, to talk to the router to get on to the internet or on the LAN.
If there are too many routers using the same channel in a close proximity, you are more likely to experience a slower connection, connection dropouts, general interference and other problems.

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Installing TCPDump on DD-WRT WRT54GL

This article will serve as a quick tutorial on installing TCPDump on a LinkSys WRT54GL box running the custom DD-WRT firmware.

TCPDump is a command line packet analyser. It’s a bit like Wireshark except it is command line based and in this tutorial, we will be installing it on a router and not on a PC.
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