The disclosed embodiments relate to a system for selecting an interface for routing an outbound packet. During operation, the system receives an outbound packet to be routed to a destination address. Next, the system obtains application-layer data associated with the outbound packet, including one or more of a process identifier, an application identifier and a user identifier. The system then selects an interface through which to route the outbound packet based on the application-layer data, and uses the selected interface to route the outbound packet.