SkypeShield has added a new strong authentication solution, which enables the ability to limit access to the organization's Skype for Business (Lync) server only to corporate devices, adding another layer of security to the authentication process. This is done, by using an innovative IP Filter  (IPF), which was developed by SkypeShield, following specific customer requests. SkypeShield's IPF can be implemented at the registration process or during the ongoing usage of Skype for Business. Registration filtering enables control on the devices that can complete the registration process and filtering on the ongoing controls from which location connection is allowed. By using our IPF, registration can be limited to a specific IP range that is accessible only from within the corporate network, thus blocking attempts to register a device without being able to join the corporate network. SkypeShield's IP Filter is an ideal solution for organizations that limit the connection to a specific network by using certificate or Mobile device Management (MDM) solutions. This allows verifying, for example, that only devices with an installed MDM can use Skype for Business. Applying the IPF for the Skype for Business usage can be transformed into geo-location protection by limiting the connection to specific countries based on IP range.