The IRequest::get_ServerVariables method retrieves the ServerVariables collection of the Request object.
HRESULT get_ServerVariables(
IRequestDictionary ** ppDictReturn // pointer to an
// IRequestDictionary interface
// pointer that receives the
// ServerVariables collection
);
You can iterate through the ServerVariables collection with the IRequestDictionary::get__NewEnum, or you can retrieve a specific ServerVariable with the IRequestDictionary::get_Item method.