Abstract: Methods, systems, and devices are described for stateful failover in traffic manager module functioning as a proxy between at least one first network device and at least one server. In a first set of embodiments, an amount of synchronized state information may be reduced through a controlled use of acknowledgment messages. In a second set of embodiments, state information may be synchronized to a standby traffic manager module in response to changes in a sequence number delta between two logically paired connections. In a third set of embodiments, connections may be restored at a standby traffic manager module based on stored connection information, a synchronized sequence number delta stack, and rediscovered sequence numbers.