An enterprise system configured to control mobile device accesses to enterprise resources, the enterprise system comprising: an enterprise resource configured to electronically communicate with computing devices over a communication network; and a gateway comprising computer hardware, said gateway configured to: receive a request from a mobile device to access the enterprise resource, the request formatted according to a protocol that includes one or more properties associated with the mobile device; receive gateway rules from one or more gateway rule providers, each gateway rule comprising: one or more values of one or more of said properties of the protocol; and an indication to take a selected action, when the request has one or more property values that correspond to the one or more property values of the gateway rule; determine whether the request has one or more property values that correspond to one or more property values of any of the gateway rules; and when the request has one or more property values that correspond to one or more property values of one of the gateway rules, cause the action indicated in the one gateway rule to be taken based on the indication in the one gateway rule, characterized in that the selected action comprises encrypting an email attachment sent to the mobile device, and characterized in that the gateway is configured to determine whether to encrypt the email attachment sent to the mobile device based on the one or more mobile applications stored on the mobile device. an enterprise resource configured to electronically communicate with computing devices over a communication network; and a gateway comprising computer hardware, said gateway configured to: receive a request from a mobile device to access the enterprise resource, the request formatted according to a protocol that includes one or more properties associated with the mobile device; receive gateway rules from one or more gateway rule providers, each gateway rule comprising: one or more values of one or more of said properties of the protocol; and an indication to take a selected action, when the request has one or more property values that correspond to the one or more property values of the gateway rule; determine whether the request has one or more property values that correspond to one or more property values of any of the gateway rules; and when the request has one or more property values that correspond to one or more property values of one of the gateway rules, cause the action indicated in the one gateway rule to be taken based on the indication in the one gateway rule, characterized in that the selected action comprises encrypting an email attachment sent to the mobile device, and characterized in that the gateway is configured to determine whether to encrypt the email attachment sent to the mobile device based on the one or more mobile applications stored on the mobile device. receive a request from a mobile device to access the enterprise resource, the request formatted according to a protocol that includes one or more properties associated with the mobile device; receive gateway rules from one or more gateway rule providers, each gateway rule comprising: one or more values of one or more of said properties of the protocol; and an indication to take a selected action, when the request has one or more property values that correspond to the one or more property values of the gateway rule; determine whether the request has one or more property values that correspond to one or more property values of any of the gateway rules; and when the request has one or more property values that correspond to one or more property values of one of the gateway rules, cause the action indicated in the one gateway rule to be taken based on the indication in the one gateway rule, characterized in that the selected action comprises encrypting an email attachment sent to the mobile device, and characterized in that the gateway is configured to determine whether to encrypt the email attachment sent to the mobile device based on the one or more mobile applications stored on the mobile device. one or more values of one or more of said properties of the protocol; and an indication to take a selected action, when the request has one or more property values that correspond to the one or more property values of the gateway rule; determine whether the request has one or more property values that correspond to one or more property values of any of the gateway rules; and when the request has one or more property values that correspond to one or more property values of one of the gateway rules, cause the action indicated in the one gateway rule to be taken based on the indication in the one gateway rule, characterized in that the selected action comprises encrypting an email attachment sent to the mobile device, and characterized in that the gateway is configured to determine whether to encrypt the email attachment sent to the mobile device based on the one or more mobile applications stored on the mobile device.