Feb 12

PowerShell™ Notes for Professionals & other books

Stack Overflow used to run an interesting project – Stack Overflow Documentation. It is currently shut down, but thanks to it we now have interesting free books like “PowerShell™ Notes for Professionals book“:

Please keep in mind it was created by SO content that may not be very accurate, like what I’d recently discovered:Are the cmdlets in a pipeline executing in parallel?

Anyway I’d recommend it since it contains an essentials compilation of PowerShell common tasks and language specifics.Good reading indeed!

There are also other books that may catch your interest:http://books.goalkicker.com/

Feb 12

How force your laptop to use GPU enabled card instead of Intel HD Graphics adapter

Windows Fall Creator’s Update for windows 10 have introduced one very neat feature: GPU tabs & other GPU related information in Task Manager:

Pretty nice indeed!

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Feb 08

Hyper-V error: External Ethernet adapter XYZ is already bound to the Microsoft Virtual Switch protocol

When you try to add a new vSwitch that is bound to a physical adapter in Hyper-V, you may receive the following error:

In this case go to network settings and find the affected adapter. Then in Properties remove the checkbox that binds Microsoft Virtual Switch protocol and press OK.

Try to create the vSwitch again.

Feb 02

Running Adafruit Feather HUZZAH ESP8266 with external power supply (3.3V / 5V)

Usually you use a usb cable to power and programAdafruit Feather HUZZAH ESP8266 via the mini usb port:

But what if you want to use external 3.3V (or 5V) power supply? To which pin should you connect it?

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Jan 19

How do Sonoff devices work?

A while ago Jan Almeroth have done excellent research on how Sonoff devices operate. Thanks to his (and many others’) work, projects like SonOTA are now possible. I’ll try to summarize the information in this article.

1. Overview

It appears that sonoffs areIoTgocompatible devices.IoTgo platform was created by Itead and aims to facilitate easier integration between IoT devices and Applications.It mainly consists of three parts:

  1. Devices ⇔ Server (left part) – devices connect to the server via HTTP/WebSocket, register and update their parameters. The server can send control commands using push notifications (via WebSocket);
  2. Apps ⇔ Server (right part) – IoTgo Apps use server gather information about devices (+their status) and control them;
  3. Web interface ⇔ Server (not shown) – used for device management;

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Jan 18

What is Sonoff and how to configure it

Remote switches, Internet of Things (IoT) and Smart home in general are quite trendy nowadays. There are plenty of trademarks and devices that allow you to switch lights, heating, garage doors etc via an application on your mobile / web page.

There is one very popular gadget among the Smart housers – the Sonoff. It is actually a trademark that includes various kinds of remote switches. Sonoff devices are getting more and more popular these days because they are small, cheap, cloud ready, easy to use and have built-in AD/DC converter (i.e. no external power supply is needed, just a cable to plug it in the grid). Some sonoffs can be controlled via RF keyfobs.

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Jan 10

Dynamic Objects in Active Directory

Sometimes we need to create users/groups/computers in Active Directory that will be used temporary (by a contractor, for testing etc.). The typical workflow is: Create > Use for a while > Delete. The deletion is manual and often these objects are being forgotten which poses some security risks.

It is little known fact that we can create the so called Dynamic objects (DOs, a.k.a. temporary objects) that get deleted from AD automatically when the associated TTL expires. Microsoft added this capability in Windows Server 2003. In fact the “Dynamic object” is an auxiliary class (OID = When linked to an object it adds some new attributes like the entryTTL (Entry-TTL) and ms-DS-Entry-Time-To-Die attribute.

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Jan 05

WinRM would not listen on port 5985

The WinRM was configured to allow remote administration via a GPO but it wouldn’t let us connect with Enter-PSSession. The firewall rule was there passing the traffic on TCP port 5985.

Checking WinRM config showed something strange:

Listener [Source=”GPO”]
Address = *
Transport = HTTP
Port = 5985
Enabled = true
URLPrefix = wsman
ListeningOn = null

So WinRM was actually configured but wasn’t listening on any network interface. Why?

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Jan 03

What is Add-PrinterDriver actually used for?

As of Windows 8.1 / Server 2012 R2 there is one beautiful cmdlet -Add-PrinterDriver. It dramatically simplifies driver/printer installation.

Naturally you will be tempted to install a driver from an .inf file like this:

But you will be blamed:

So it does not work as you/we may think. Sigh… So then what it is used for?

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