Although mobile devices are similar to laptops and desktops in many ways, the differences are striking. It’s critical to choose a firewall with a small footprint - that is, a modest use of power, storage and memory - on the mobile device.

Even as storage gets cheaper, your users’ devices become voracious animals gobbling mega- and gigabytes by the minute, and much of the available space is already taken. Therefore any business-critical application that you want to run - the firewall clearly fits that bill - must be small enough not to interfere with your users’ lives. It should go about its tasks as unobtrusively as possible.

The traditional firewall vendors - TrendMicro, Symantec, and the like - offer versions of their products for the mobile device. When you choose a firewall, scrutinize each product to see where the vendor has drawn upon heritage solutions - where size was not the biggest concern - to deliver a device version of the same product.?

Determining the memory footprint of your firewall application for your mobile device is not a straightforward process. If you use a system monitoring application like the System Activity Monitor for the iPhone or System Monitor for the Android, you can see the baseline memory usage. Subsequently install the firewall application and note the new memory usage. The difference between the two is the memory footprint of your firewall application.

Contrast this with some of the “mobile only” firewall vendors, such as Lookout and SMobile (now part of Juniper), who have had the luxury of designing their device solutions from the ground up. Their products are optimized for Internet-connected use but may lack some advanced firewall features that the traditional players have had for years.

All in all, it’s a potpourri of vendors and solutions out there, and you have to balance the “small footprint” requirement against the “best features” and “most bang for the buck” criteria when you evaluate their offerings.

You first want to ensure that your enterprise policy is being adequately met in terms of the features that the firewall vendor provides. The footprint should be your next immediate consideration and not the other way around.

Some vendors may have optimized their solutions for particular operating systems or specific devices. Make sure the solution you choose fits what your people are using. Identify the top two to three devices in your enterprise and run the “footprint” test against all of them. You don’t want to be lulled into a false sense of security by a device-specific solution, only to be rudely surprised later. Be sure to do your homework thoroughly.