AppGate, which makes its own flavor of VPN gear, has developed a VPN client for the open software platform for mobile phones known as UIQ3.

The client will enable phones to connect to an AppGate Mobility Server, the equivalent of a VPN gateway in the AppGate architecture. A secure connection can be established between the phone and the server.

Rather than standard IPSec or SSL VPN technology, AppGate uses a browser that supports the standard secure shell (SSH), the highly regarded authentication and encryption technology that runs at the application layer.

Using SSH, the phone can make encrypted connections back to a corporate site that has a Mobility Server installed behind the firewall. The devices can secure such links using 128-bit Advanced Encryption Standard (AES), which is one of the options available with IPSec.

The client and Mobility Server expand the capability of the phone's browser from just receiving e-mails pushed by an e-mail server to being able to access a variety of corporate applications. So if a Web app can be presented readably on a phone screen, phones with the client can access it.

This system may pose some security problems because it allows downloading what may or may not be sensitive data that would reside on the phone even if the phone gets lost. So it may be in the business's best interest to choke off access to data that must remain secure.

The new client works on any phone running the UIQ3 mobile platform, and that includes several Sony Ericsson models.

Tim Greene is senior editor at Network World.