Skype is a proprietary software application which allows users to make inexpensive or free voice calls over the Internet. Skype also supports video conferencing for as many as ten users.

Skype is not a supported application at Penn, but is in fairly common use at the University. If you are considering the use of Skype, we encourage you to be aware of the risks and some of the ways you can mitigate them. Skype is a peer-to-peer application, which means that computers with Skype allow anyone in the world to connect to them, even if they aren't making a Skype call to that user. This helps Skype efficiently route calls around the world, but also leaves your computer open to connections from anywhere in the world. In its default configuration, Skype runs continuously in the background so that your computer can serve as a "supernode" in support of other user's Skype calls. Turning Skype off when it is not in use reduces the chances that your computer will be used in this way, which improves performance and reduces the security risks associated with use of peer-to-peer applications.

To mitigate use and improve performance follow these recommendations:



Modify these settings in the Options... dialog box in the Tools menu (most changes require you to be logged in):

In the Connections section of the Advanced tab, change the Use port for incoming connections field to 18019.
In the Connections section of the Advanced tab, ensure that the Use port 80 and 443 as alternatives for incoming connections checkbox is not checked.


Modify these settings in the Preferences... dialog box in the Skype menu (most changes require you to be logged in):

In the General tab, ensure that the Check for updates automatically checkbox is checked.
In the Privacy tab, ensure that the Enable Bonjour checkbox is not checked.
In the File Transfers tab, ensure that the Automatically accept files checkbox is not checked.
In the Advanced tab, change the Incoming connection port: to 18019.


  • Using Skype for video conferencing requires both participants to have a current version of the Skype application installed.
  • Video conferencing requires more network bandwidth than an audio call, and so will be more sensitive to network issues that impact quality of service.
  • International video conferences are more likely to suffer degradation of service quality as they have to traverse more networks to reach their destination.
  • When possible, use Skype on wired PennNet rather than on AirPennNet, as this provides a dedicated connection for more consistent performance.
  • When using Skype on a mobile device, performance will generally be better using WiFi than a cellular network.


  • Do not have the Skype application automatically sign in when starting your computer or the Skype application.
  • Only launch the Skype application when you need to use it.
  • When the video conference is finished, quit the Skype application. Closing the Skype application window in Windows is not enough; the background application must be turned off as well via the system tray icon.
  • Always ensure that your antivirus software (Symantec Endpoint Protection for Windows or Norton AntiVirus for Mac OS) is running and up-to-date.
  • Do not use the same password for Skype (or other peer-to-peer services) as you use for other logins (such as online banking or email).
  • When traveling to certain international destinations, particularly China, care should be taken to install Skype before leaving the US, as attempting to install from within the country may result in a different version with questionable security.
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Date Posted: March 12, 2013 Tags: Provider Resource, Conferencing, Chat

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