Systems and methods of the present disclosure relate to allocating ports for packets distributed via a computer network. A packet engine on a core of a multicore device intermediary between a client and a server receives a first packet from the client. The first packet includes an outer header of an encapsulation protocol encapsulating a payload with an inner header. The first packet is directed by a packet distributor of the device to the first core selected based on a first tuple of the outer header. A port allocator of the packet engine determines a source port number to cause the packet distributor to identify the first core based on a second tuple of the inner header. The packet engine modifies the inner header of the payload to include the determined source port number. The device forwards the first packet including the modified inner header to the server.