Skype Usage
at
Brookhaven National Laboratory
 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.
What is a SuperNode? Hide Text
A SuperNode can generate a considerable amount of traffic by
opening a large number of concurrent connections for off-site systems, even
after the local user has discontinued using the Skype
application on their system. Generally, the user needs to reboot their system to
stop the SuperNode call-routing activity.
Because SuperNodes can generate excessive amounts of non-mission traffic and
raise potential public embarrassment concerns regarding inappropriate use of
government-funded resources, acting as a Skype SuperNode
is considered a violation of the BNL
Computer Use
Agreement. Systems that become Skype SuperNodes on the BNL network
will be blocked from the 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:

Skype Guidelines
- 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.
- 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:
- On the toolbar in Skype
go to [Tools] [Options].
-
Click here
to view example image.
- When the Options window appears click on the
advanced tab on the left side at the bottom.
- At the top of the advanced screen under Startup
uncheck the first box labeled "Start Skype
when I start Windows".
- Continue by selecting Save at the bottom of the
window.
- 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

Last Modified: April 28, 2011 Please forward all questions about this site to:
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