we have used remote_max_parallel = 20 for a long time and it worked
fine. But currently we cannot deliver emails to a big German ISP
(t-online), because their mailservers respond with
421 IP:x.x.x.x - Maximum parallel connections for your IP-Address reached
It seems, that are allowed to use only one connection at a time. Thats
not much, but since other ISPs allow much more connections, we don't
want to reduce remote_max_parallel to 1 for all mailservers.
How can we set this value depending on email-addresses (to match
@t-online.de addresses or mailservers ending with .t-online.de)?