Middleboxes include a processor configured to determine a degree of mismatch between a sequence number in a first connection between the middlebox and a client device and a sequence number in a second connection between the middlebox and a server device. A network control module is configured to delay acknowledgment signals from the middlebox on a connection to decrease the degree of mismatch between sequence numbers and to establish a direct connection between the client device and the server device without mediation by the middlebox upon a determination that the degree of mismatch between sequence numbers is zero.