Abstract: Wide Area Network optimization is described. In an embodiment, a first proxy server computer intercepts a first message from a client computer to a server computer along a routing path. The first proxy server computer modifying the first message to include an indication that the first proxy server computer is along the routing path. The first proxy server computer forwarding the first message to a next hop of the routing path. The first proxy server computer receiving a message from a second proxy server computer indicating that the second proxy server computer is along the routing path. The first proxy server computer, in response to receiving the second message, enabling a set of optimizations for traffic traveling between the client computer and the server computer.