Siebel System Requirements and Supported Platforms > Hardware and Network Requirements >

Firewall Proxy/Reverse Proxy Support

Firewall proxies and reverse proxies implemented in conjunction with Siebel applications are supported with HTTP 1.0 or 1.1 protocol. Special deployment considerations should be made when using proxies that support HTTP 1.0. See Siebel Installation Guide for the operating system you are using for details about installing the Siebel Web Server Extension.