T-Mobile has installed a firewall on its GPRS network in the States after a small number of users complained of receiving hacker probes when using its high-speed mobile service.

The issue came to light after Mike Palmer, the technology director for the broadcast division of AP, spotted numerous probes against his PC while using T-Mobile's GPRS network, Computerworld reports.

T-Mobile admitted to Computerworld that around 100 users were affected by the issue, prior to the recent introduction of a firewall on open segments of its GPRS network. Palmer told reporters that he's not spotted probes since then.

Like DSL broadband, GPRS networks offer an always on connection - hence a greater need for firewall protection both from service providers and end users than for dial-up connections. If mobile operators haven't this technology in place already, they ought to review their security policies pretty darn quick.

"GPRS is an 'always on' service, with your IP address being propagated to a greater or lesser extent
throughout the wireless network," Neil Barrett, technical director at security consultants Information Risk Management told us. "I'm not aware of any personal firewall products for GPRS-enabled handhelds, and I'd have to suggest that there's a market there waiting for someone to rip into."

Barrett said if a user's GPRS has a Bluetooth connection to a laptop, which has a personal firewall installed, that partially addresses the security issue. But that's not the only issue to consider.

Since GPRS services are normally paid for by the volume of traffic used, hacker probes could end up costing end-users money as well as threatening their security.

"I love the idea of people having to pay for the hacker traffic that's attacking them," Barrett wryly notes. ®

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