I recently had to move servers. On the old server, I had a Mailman listserv distribution list, but since Mailman was not supported on the new server, I wrote up a PHP script to read messages from IMAP and resend via SMTP. The script is brittle (my fault) and complex (not my fault): I'm having to parse each message, find the bits that I can use (if it's multi-part or HTML or it has attachments), and then reconstruct the message for SMTP so that each member except the sender gets a copy and the Reply-To is the distribution list address. The thing is, I know that the raw source of the message is fine as is. I just need to change/add a few headers.
On Windows servers, you can configure an email dropbox folder where you could save outgoing mail messages in their raw form. Is there anything similar on *nix? Is there any other method I should look at?
I know I can set up a forwarder address on the server, but I really like the behavior of listserv systems: senders don't get a copy of their own message, the subject is identified with the list's label and hitting "Reply" sends a message back to the distribution list, not the original sender.