In storage networks (e.g., SAN and NAS), various reasons can arise for migrating an application layer communication session endpoint to a different host. To achieve scalability and robustness, the migration can be enacted externally and carried out at a middlebox at the transport layer. When a migration is triggered to migrate an application layer communication session endpoint from a host A to a host B, the middlebox coordinates network address translation with a transport protocol reset mechanism to switch the connection to host B and close the connection on host A with minimal disruption to the non-migrating application layer communication session endpoint using the connection. At the application layer, the non-migrating application layer communication session endpoint will initiate a new connection in response to detecting the reset, and retry any operation that was aborted as a result of the connection switch.