Skype Usage

at Brookhaven National Laboratory

 

Skype Logo

Introduction

Skype is a free P2P (peer to peer) application that provides free voice-over-IP communication over the Internet. The use of Skype on systems attached to the Laboratory network is allowed for systems categorized at the Low risk level but is prohibited on Moderate risk systems.

Skype computer calls are routed across the Skype network through other Skype systems, called SuperNodes. Any system running the Skype application runs the risk of surreptitiously being elevated to the status of SuperNode. Computers with a fast connection to the Internet, combined with high speed CPUs, are most likely to become SuperNodes within the Skype network.

The following procedures have been developed to configure systems to run the Skype application, without becoming a SuperNode. These steps work on Windows XP systems, however the general approach and configuration settings should be applicable to other platforms & operating systems. These procedures work with version 2.0.0.97 of Skype. There is no guarantee these procedures will function properly in future releases.

Based on this general information and the guidelines below, Skype can be installed and used on the BNL network by implementing the following configuration on the user’s system:

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Skype Guidelines

  1. For Windows, Linux or Mac OS the most current version of Skype should always be used. Skype will require an Administrator right to be installed, but you should run it with a non-administrator account to prevent Skype from changing your Windows firewall rules.
     
  2. The user should insure that Skype is not loaded at startup and is only running while the user is at the computer to receive or make calls. There are two ways to ensure that Skype does not start when Windows starts.

    Option 1:
    On the Sign-in window in Skype uncheck both boxes labeled "Start Skype when the computer starts" and "Sign me in when Skype starts" as shown on the example image. Continue to sign-in normally.

    Option 2: 
    If your Skype application is already running you can disable it from starting when Windows starts by:
    1. On the toolbar in Skype go to [Tools] [Options].
         - Click here to view example image.
    2. When the Options window appears click on the advanced tab on the left side at the bottom.
    3. At the top of the advanced screen under Startup uncheck the first box labeled "Start Skype when I start Windows".
    4. Continue by selecting Save at the bottom of the window.
       
  3. A software firewall must be installed and enabled.
    Windows XP firewall or Zone Alarm are examples of suitable firewalls for XP.

    How to enable the Windows XP Firewall:
    This is done using the Administrator account.

    [Start] [Settings] [Control Panel] [Security Center] Windows Firewall (at bottom)
       - Click the "General" Tab.
       - The check box On (recommended) should be selected.
       - Click here to view example image.

    Exceptions for Skype must be disabled or deleted in the firewall setup.
       - Click the "Exceptions" Tab.
       - Locate Skype and make sure the box is unchecked.
       - Click here to view example image.

     Press Ok and close the Security Center window.

Using a non-Administrator account for Skype and the above firewall configuration should prevent the local system from becoming a SuperNode.

All Skype user's should read and fully understand the Skype End-User License Agreement

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Last Modified: April 28, 2011
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