How do I prevent someone from pushing content to my BlackBerry wireless device?

The BlackBerry Mobile Data Service push service accepts HTTP POST's from any source. Assuming the destination and payload are valid, it sends the push as requested. Since the Mobile Data Service server is located behind the corporate firewall, only those who are connected internally and have access to the corporate network can access the Mobile Data Service to initiate a push request. The administrator can implement further restrictions using firewall technology or the Windows TCP/IP configuration settings. These two options may be used to reject inbound connections on the push port except from authorized applications. The newest versions of Mobile Data Service are expected to provide more granular security options.