A method for a computing device (102; 202; 502), the method comprising: establishing a communications channel with a mobile communications device (104; 204; 504), wherein the mobile communications device (104; 204; 504) has a connection with an enterprise network (108; 208b; 512, 530); establishing one or more communications sessions over the communications channel, including at least a first communications session associated with a first proxy of the mobile communications device (104; 204; 504); providing a limited access privilege to a first security perimeter of the computing device to utilize the first communications session, the limited access privilege allowing limited connectivity of an enterprise management application in the first security perimeter of the computing device to attempt to establish a connection with a service at the enterprise network (108; 208b; 512, 530) via the first communications session; and selectively providing an access privilege to the first security perimeter of the computing device, the access privilege allowing applications of the first security perimeter to utilize the first communications session for further communications, said providing based upon whether the attempted connection with the service at the enterprise network was established via the first communications session; characterised in that, when the attempted connection with the service at the enterprise network is not established and the computing device and the mobile communications device are associated with different enterprises, disabling the first communications session, establishing a new security perimeter on the computing device, with a port and establishing a second communications session over the communications channel between the port of the new security perimeter and a second proxy of the mobile communications device, the second communication session not associated with the said first proxy. establishing a communications channel with a mobile communications device (104; 204; 504), wherein the mobile communications device (104; 204; 504) has a connection with an enterprise network (108; 208b; 512, 530); establishing one or more communications sessions over the communications channel, including at least a first communications session associated with a first proxy of the mobile communications device (104; 204; 504); providing a limited access privilege to a first security perimeter of the computing device to utilize the first communications session, the limited access privilege allowing limited connectivity of an enterprise management application in the first security perimeter of the computing device to attempt to establish a connection with a service at the enterprise network (108; 208b; 512, 530) via the first communications session; and selectively providing an access privilege to the first security perimeter of the computing device, the access privilege allowing applications of the first security perimeter to utilize the first communications session for further communications, said providing based upon whether the attempted connection with the service at the enterprise network was established via the first communications session; characterised in that, when the attempted connection with the service at the enterprise network is not established and the computing device and the mobile communications device are associated with different enterprises, disabling the first communications session, establishing a new security perimeter on the computing device, with a port and establishing a second communications session over the communications channel between the port of the new security perimeter and a second proxy of the mobile communications device, the second communication session not associated with the said first proxy.