In this paper, we present the approach and architecture of TARGET: Two-way Web Service Router Gateway, for two-way web service interaction crossing enterprise domain and firewall. It provides a full support for asynchronous outbound operation and event notification in communication services. TARGET addresses an acute issue for internet applications that today?s enterprise NATs and firewalls only allow outbound HTTP request from the inside to the outside and block any request from the outside to the inside, which is a serious problem for two-way web services. TARGET is a generic solution to allow two-way web service interaction to traverse legitimately through NATs and strictly configured firewalls; and it is based on two-way SOAP message tunneling, service local registry, and service routing to bridge two-way web service interaction. A research TARGET system has been implemented and applied to real time communication services, e.g. conferencing. Extensive experiments on TARGET are performed, and its performance with various sizes of SOAP messages is studied. The applicability and feasibility of TARGET for two-way web service interaction is verified.