Hello everyone,

I'm setting up a Courier Mail Server v0.47 under Suse Linux 9.0 with a Dial-up Internet connection and a smarthost configuration: every outgoing mail will be forwarded to an ISPs Mailserver (using SMTP Auth). Therefore the Courier "esmtproutes" file looks like: ": smtp.1und1.com".

Because of the limited bandwidth I expected Courier in a smarthost configuration to forward every message as one message to the providers smarthost. But in fact Courier splits every mail with multiple recipients into a number of messages (according to the used mail domains: one mail per destination domain). "mailq" lists the message immediately after having received it from the client as one. But as soon as forwarding to the relay/smarthost starts, the mail will be splitted into different ones (the forwarding to the smarthost then seems to work fine).

I could'nt found why Courier behaves like this nor how to adjust it. As far as I can see RFC 2821 recommends: "When a mail message is to be delivered to multiple recipients, and the SMTP server to which a copy of the message is to be sent is the same for multiple recipients, then only one copy of the message SHOULD be transmitted." and "When the same message is sent to multiple recipients, this protocol encourages the transmission of only one copy of the data for all recipients at the same destination (or intermediate relay) host."

Just looking in the mail archive (From: Jeff Jansen <ivb_tech@si...> Re: Multirecipient mail routing, 2003-06-04 14:39) I saw there was a similar question placed before, obviously solved by a "private patch". Is there meanwhile an official solution available?

I appreciate any hints!

Regards,