An integrated, multi-service network client for cellular mobile devices is described. The multi-service network client can be deployed as a single software package on cellular mobile network devices to provide integrated services including secure enterprise virtual private network (VPN) connectivity, acceleration, security management including monitored and enforced endpoint compliance, and collaboration services. Once installed on the cellular mobile device, the multi-service client establishes the VPN connection to concurrently include both a layer three (L3) tunnel that uses a first type of transport layer protocol of the operating system and a layer four (L4) tunnel that uses a second type of transport layer protocol of the operating system. The VPN handler determines whether network ports associated with the L3 tunnel are unblocked by an operating system and, when the network ports are unblocked, automatically transitions from the L4 tunnel to the L3 tunnel without terminating the VPN connection.