Friday, April 11, 2014

"Heartbleed" SSL bug, what should you do?

It seems like everyone (online and offline) is talking about the "Heartbleed" SSL bug.  To over simplify how it works, a malicious user or program can make a call to a remote server and request information from it's memory which can include information such as encrypted versions of a username and password.

The following XKCD comic does a great job in making this bug more understandable for those that might not understand the technical underpinnings of SSL.

If you want to know what to do, there are a few things you should know.  First of all this bug only effects Linux servers using an older version of an open source SSL implementation.  So not all web sites are effected, because its not a problem with the SSL technology.

Second, most of the large popular sites that were effected by it should have patched their servers by now. Some sites have already send out notifications to users to change their password.

If you're worried about a specific web site/account, go ahead and change it just to be on the safe side.  When dealing with the Internet it never hurts to be too careful.

Monday, April 07, 2014

Script: World Simplest Network Scanner (Class C)

Note: This tool requires an understanding of IPv4 networking to utilize it.
If you have a small home or business network, and need a way to find all the devices that are attached to it, then you can use a program called a "network scanner".  It will try to find all the visible devices (i.e. without a firewall blocking outside network access) on a network using various different techniques.

A simple way of mapping the visible devices on your network, that doesn't require the use of any extra tools.  Paste the following line into the command prompt:
for /l %i in (1,1,255) do @ping -n 1 192.168.1.%i | find /i "bytes="
Notes: 

  • You might have to modify the text in red so matches the network segment you want to scan.
  • There are more robust 3rd party network scanners available.  Check your favorite tool site to see what they may offer.
  • Another trick that can be use to find out this information check your router or DHCP server to see what devices have requested a dynamic IP address.

Monday, February 17, 2014

Troubleshooting: Wireless Network Antennas

In a previous article I talked about a software tool for troubleshooting problems with a wireless network signal.  This article focuses on the antenna and related technologies.  I will do my best to keep the subject matter of this article so that its understandable.  Although, the terminologies and concepts can quickly become confusing.

When troubleshooting a wireless network problem, it’s important to have a good understanding of the basic technology in order to solve problems with it.  One of the primary components of any wireless network is the antenna.

The primary antenna issue with most wireless networks is the range of the signal.  To help extend the range of the WiFi device, there are a few things that can be done.

  • Try moving the WAP to a new location.  Ideally it should be centrally located in a structure, unless you're broadcasting the signal between two points.
  • Try to create one of the many DIY wireless signal enhancers that are available on the Internet (see the reference area below).
  • Buy a better antenna for the WAP or wireless network card (if the device supports this option).
    • Note: there are a few different types of common antenna connectors
  • Buy a WiFi signal booster/extender/repeater to extend the range of the signal.  There are a few different types of these devices, research will be needed to find the one that will best meet the requirements of the network.
    • Note: If considering a high-power antenna or some type of signal booster, the FCC limits the maximum transmission power to 1 watt, or about 36 dB.

There are some important terms to know about WiFi networking to have a greater understanding of the technology:

  • 802.11: The international wireless networking protocol standard.  There are currently six versions of this protocol (801.11/b/a/g/n/ac).  Each version of the protocol is faster then the previous.
  • Attenuation: The loss or weakening of a signal through its transmission.
  • Direction: There are generally two types of antennas: unidirectional (one direction) and omni-directional (all directions).  Unidirectional antennas are for point-to-point communication.  Omni-directional antennas are for point-to-multipoint communication.
  • Frequency: The two main frequencies that are used in 802.11 wireless networking are: 2.4GHz and 5GHz.  The 2.4GHz frequency is the most popular, and often the noisiest.
  • Gain: A measurement of the antenna's signal and typically measured in dB (decibels).
Additional Resources:
  • DIY WiFi Antenna booster: Ez-12 Parabolic Reflector Template
  • When buying a new antenna for a wireless device, there are few basic types of 802.11 antennas.  Depending on the wireless network setup, some of these may be able to help boost the signal or range.
    • Parabolic: supports a unidirectional signal, can look like a satellite dish.  Generally used for sending a signal between two specific points.
    • Yagi: supports a unidirectional signal, the core antenna can be covered with a plastic tubular housing (it can also look like an older style TV antenna).  Like a Parabolic antenna its used for sending a signal between two specific points.
    • Dipole: omni-directional signal (signal goes in all directions).  This is the most common WiFi antenna, it can cover a wide area (generally a few hundred feet), but wastes a lot of energy because the signal radiates in all directions.

Monday, February 10, 2014

Troubleshooting: Wireless Network Signal Problems

Have a WiFi network and not sure why you're not getting a good signal from the wireless access point (WAP) or router?  There could be several possible problems, for example:
  • The WiFi device is too far away from the WAP to send or receive a radio signal. 
    • Tip: Most WAPs use a type of vertical omni-directional antenna that broadcasts a signal that would look like a big doughnut.  Try pointing the antenna where the other wireless devices are located.
  • The building structure (i.e. walls depending on their material) can prevent the signal from reaching the wireless device.
    • Note: WiFi signals can be blocked by objects containing water (e.g. water heaters, fish tanks, water coolers, etc.)
  • Electromagnetic interference from devices like microwave ovens or cordless phones all share the same frequency (2.4GHz) that is used by 802.11 networking.
  • Too many other WAPs around the device, and they're causing interference.
With the free home version of the inSSIDer WiFi Scanner its possible to graphically see what is happening with all the other wireless signals around.  This may help find a channel in the local area that is being under utilized to get a better connection.  If necessary, try relocating the WAP or router to a different location to see if that solves the problem.

Watch the video to get more information, and to see a demonstration of the application.  The company does provide a more advanced version of the product for purchase, check out their site for more information.




Monday, February 03, 2014

Windows 8 Tip: Power User Menu

WinKey + X: Displays the Power User menu, which grants quick access to administrator functions and tools such as the command prompt, computer management console, and more.

Note: To add (or delete) shortcuts to utilities in this menu, open the following path in the File Explorer %UserProfile%\AppData\Local\Microsoft\Windows\WinX.

For more Windows 8 Keyboard Shortcuts.


Monday, January 27, 2014

Windows 8: Change File Explorer Default Open Location

Did you know you can change the File Explorer's (formerly known as Windows Explorer) default behavior of opening the Libraries folder?  Its just of matter of changing the shortcut's properties to something that you would prefer instead.

Follow the instructions below:
  • Press the WinKey + D to show the desktop.
    • Note: Its important to close all the File Explorer windows.
  • Hold down Shift and Right-click on the Explorer icon in the taskbar, and select Properties.  
    • Note: you can also make your own shortcut by right-clicking an empty area on the desktop and selecting New > Shortcut, just follow the instructions in the wizard.  Paste any of the command paths below into the Type the location of the item field, press the Next button, give your new shortcut a name, and press the Finish button.
  • In the Shortcut tab, in the Target field you can specify the path to the new location that you want to use. For example, use one of the following paths (by default its: %UserProfile%\AppData\Roaming\Microsoft\Windows\Libraries):
    • To open Computer folder (show all drives attached to the computer):%SystemRoot%\explorer.exe /root,::{20D04FE0-3AEA-1069-A2D8-08002B30309D}.  The Control Panels folder is: %SystemRoot%\explorer.exe /root,::{20D04FE0-3AEA-1069-A2D8-08002B30309D}\::{21EC2020-3AEA-1069-A2DD-08002B30309D}
    • To specify a specific path, use: %SystemRoot%\explorer.exe C:\Users (change C:\Users to be any path you want)
  • Press the OK button when done.
Bonus tip:
  • Use the /select,"object": To specify a file or folder to receive the initial focus.
    • For example: %SystemRoot%\explorer.exe /select,c:\windows\system32\calc.exe (To select the CALC.EXE in the C:\WINDOWS\SYSTEM32 folder)

Monday, January 20, 2014

Windows 8: Checking Activation Status

Are you a user of Windows 8 Professional or Enterprise edition and would like to check the status of activation on the local computer? Want to make sure that the computer is connected properly to the Key Management Server (KMS) or used your Multiple Activation Key (MAK) properly? Or are you a home user and just want to make sure your computer is fully activated?

Included in Windows 8 (this tool was first made available in Windows Vista, so this tip will work on earlier versions of Windows) is very useful utility that will help you check the status of activation of your computer:
  • From the Start screen, type CMD and press the Enter key
  • At the command prompt, type slmgr.vbs /dli and press the Enter key (for a more detailed report run slmgr.vbs /dlv).
After a few seconds you will be presented with a pop-up message with your activation status.
Note: Windows 8 supports a new command called: LICENSINGDIAG (e.g. licensingdiag.exe -report c:\output\license_report.xml -log c:\output\license.cab), that generates a report about the activation and registration data on the local computer.  This tool appears to be some type of technical support diagnostic tool based on the way it runs.