If a gateway such as an SSL accelerator or a load balancer is placed between a client and an in-process HTTP server, when the Web container automatically redirects to a welcome file or the Form authentication window, the Web container may not properly create a forwarding URL because the container cannot acquire the information about the gateway.

To avoid this problem, you can use the gateway specification functionality. This functionality notifies a Web container of gateway information so that the Web container can properly redirect to a welcome file or Form authentication window.

The gateway specification functionality is used in the following case:

• When an SSL accelerator is placed between a client and in-process HTTP server:
  Even if a client accesses an SSL accelerator via HTTPS, the SSL accelerator accesses a Web server via HTTP, which causes the Web container to assume that the access uses HTTP. For this reason, HTTP is used for the URL scheme for the welcome file or Form authentication window that is the redirection destination.
  In this situation, by using the gateway specification function to specify that the scheme be always considered as HTTPS, you can ensure that accesses are properly redirected.
  
• When a request without a Host header needs to be redirected away from the in-process HTTP server that received the request
  When redirecting a request without a Host header, the host name and port number of the redirection destination URL becomes the host name and port number of the Web server that receives the request.
  Use the gateway specification functionality when the host name and port number of the URL accessed by the client is different from the Web server or in-process HTTP server that receives the request, such as when a load balancer is deployed before the Web server or in-process HTTP server. As a result, the host name and port number accessed from the client are specified, so the request can be redirected properly.
  

Note that when using the in-process HTTP server, gateway specification functionality cannot be used if multiple different routes are used for accessing one Web container (when HTTP requests are forwarded to the Web container from multiple gateways). To use the gateway specification functionality in the in-process HTTP server, use a configuration in which there is one access route to the Web container.