The default behavior for the RealAudio Player and the RealPlayer is to receive data packets via UDP. Some systems behind packet-filtering firewalls cannot receive UDP packets.

In some cases, switching this default to TCP can solve this problem.

RealAudio Player 2.0 and earlier:

1. Select Preferences from the View menu.
2. Select the Network tab in the Preferences dialog box. The upper-most option is Receive Audio Via.
3. Select TCP, and click the OK button.

RealAudio Player 3.0 and RealPlayer:

These version of the Player automatically detect if you cannot receive data via UDP and switch to TCP.

For more complete information on firewalls and how RealAudio and RealVideo work with them, please search the Progressive Networks Knowledge Base with the keywords "configure AND firewall".