Hi Wietse, Thank you for your reply,
That's why it wasn't working as expected !So, just to be sure, is this syntax valid (destination_concurrency_limit is this time documented in the smtp manpage) ?
transportname unix - - n - 1 smtp -o transportname_destination_concurrency_limit=3 Or do I have to use "-o smtp_destination_concurrency_limit=3" ? Regards, Msd