The recent message about proxy_add_forward reminded me of a simple change I made that might help anyone who wants to track the logs matching the source/destination of proxied requests. I also activated mod_unique_id and in mod_proxy_add_forward, after if (r->proxyreq) { ap_table_set(r->headers_in, "X-Forwarded-For", r->connection->remote_ip); I added: (too lazy to write a whole module for this...) ap_table_set(r->headers_in, "X-Parent-Id", ap_table_get(r->subprocess_env, "UNIQUE_ID")) ; Then I added elements in the LogFormat for %{UNIQUE_ID}e %{X-Parent-Id}i The result is that the UNIQUE_ID field is different on every hit and can be used as a database key. If the first server hit delivers the content directly, the X-Parent-Id will be logged as "-". If it passes the request by proxy to another server it will be the same as the UNIQUE_ID (I wasn't expecting that, but it is interesting). The machine that receives the proxy request will log the X-Parent-Id containing the same value as the sender's UNIQUE_ID which can then be used to tie them together. Les Mikesell [EMAIL PROTECTED]