Could you share more details about your use case?
Do you mean that you're not getting headers say 'X-forwarded-for' in your permission-sensitive caching enabled servlet?
Could you make sure that the header(s) are set by Load balancer or other proxies that are above apache/dispatcher?
/clientheaders in dispatcher.any would simply pass-through headers that are allowed in this configuration, it won't generate headers on its own.