Other Security Measures

The following subsections describe other security measures that you should consider when implementing your mobile solutions. You may find that some of these measures are already in place in your organization, as they are commonly used techniques for increasing overall system security.

Firewalls

Firewalls are the most common form of security implemented within organizations. They establish a network perimeter between what is public and what is private. A firewall is a set of software programs, usually located on a separate gateway server that restricts access to the private network resources from users on other networks. As soon as an enterprise installs Internet access to its site, a firewall is required to protect its own resources and, sometimes, to control outside resources to which its own users have access.

At a lower level, a firewall will examine each packet of network data to determine whether it should be forwarded to its destination. Where outside access is permitted, as in the case of a Web server, the firewall will allow outside traffic through the firewall on a specified port, for communication with a specified application. In this case, it would permit access from all outside users. At times, however, access from outside the firewall will be restricted to only known users, usually based on their IP addresses. This is used when a finite number of known users require access to a system.

For mobile devices that have always-on connections, a personal firewall may also be useful. This works in the same way as the firewall just described above, except it prevents unauthorized access to laptops and high-end PDAs. A personal firewall will prevent not only suspicious connections but also inappropriate content. Many devices contain hidden instructions that are used by maintenance professionals to repair a device. Lately, viruses and other inappropriate content have taken advantage of these hidden instructions to cause harm. A personal firewall can help prevent this from happening, although it should not be used a replacement for appropriate antivirus software.