* Wietse Venema: >> Would that not cause a prohibitively large number of open connections >> between Postfix's smtp and the sleeping proxy? > > Limited by the (master.cf) per-delivery-transport process limit, > and the (main.cf) per-delivery-transport concurrency limits.
I have written and tested a prototype based on your suggestions, which uses goroutines to proxy and delay individual connections. The results look promising so far. I hope that I will get the go-ahead to test this in an environment with a message load closer to production conditions over the next week. One question arose: Postfix documentation [1] mentions that milter header cheks allow "content inspection of message headers that are produced by Milter applications". Does Postfix keep a record of headers which have been added during milter calls, and if so, can the list of added headers be accessed and/or logged? [1] http://www.postfix.org/postconf.5.html#milter_header_checks -Ralph
