I have aliases set up in postfix, such as the following:
[email protected]:
[email protected],
[email protected] ...
When an email is sent to
[email protected], and any of the recipients in that alias is cc:ed which is quite common (ie: "Reply all"), the e-mail is delivered in duplicates. For instance, if an e-mail is sent to
[email protected] and
[email protected] is cc:ed, it'll get delivered twice. According to the Postfix FAQ, this is by design as Postfix sends e-mail in parallel without expanding the groups, which makes it faster than sendmail. Now that's all fine and dandy, but is it possible to configure Postfix to actually remove
duplicate recipients before sending the e-mail?
I've found a lot of posts from people all over the net that has the same problem, but I have yet to find an answer. If this is not possible to do in Postfix, is it possible to do it somewhere on the way? I've tried educating my users, but it's rather futile I'm afraid...
I'm running postfix on Mac OS X Server 10.6, amavis is set as content_filter and dovecot is set as mailbox_command. I've tried setting up procmail as a content_filter for smtp delivery (as per the suggestion below), but I can't seem to get it right. For various reasons, I can't replace the standard OS X configuration, meaning postfix, amavis and dovecot stay put. I can however add to it if I wish.