( see
http://www.exim.org/exim-html-4.00/doc/html/spec_29.html)
Does anyone know if it's specified in some rfc that the remote server should support this?
What I found with one particular server is that after completing the first message, if I still had the connection open and tried sending another MAIL, it would disconnect me. I tried the same sequence with other mail servers and they work, which is no surprise since I have been running this exim server for a long time without setting batch_max in the smtp transport (default 500).
I had to create a separate router and transport for this one mail server so that I could set batch_max to 1. Now it works.
Thanks,
Mike