Joern Lippold wrote:

Dear Joren,

The short answer is No, there's no "official" solution available. You have to patch courier yourself.

The long answer is that this happens because courier assigns each message to a "queue" based on the mail domain of the recipients. So the same message to user@domain1 and user@domain2 ends up assigned to two different queues: domain1 and domain2. Then when courier actually sends the message it checks the esmtproutes file and looks to see if there is any special routing. But even if both domains are routed to the same smarthost the message will still get sent to the smarthost twice, once for each queue.

I wrote a patch that changes this by consulting the esmtproutes file before the message is assigned to a queue and if it's finds a smarthost then ALL messages are put in one queue with the smarthost as the domain instead of the actual mail domain. This obviously has a slight performance hit as we're consulting the esmtproutes file a second time.

When I wrote Sam about this a couple of years ago he said that this issue affects so few people that he wasn't interested in incorporating it. And I have to agree with him. You are only the second person (after me) in the last 2 years that I've seen write about this issue.

You can get the patch at Gordon Messmer's web site:

http://phantom.dragonsdawn.net/~gordon/courier-patches/batch-through-smarthost.patch

The one on Gordon's site is against a fairly old courier version, so if you have any trouble then I'll be happy to send you the same patch against the most recent stable version of courier - 0.47.

It does mean that you have to patch the courier source each time it comes out, but with a few lines of shell scripting you can automate the whole process of extracting, patching, and making rpms.

I hope that helps.