How can I use Google Apps for users, but vps for apps?

This is easy. Linode Library has a exim-based solution, you need a "send only" mail server.

You can also install postfix and set it to loopback-only, I believe. I use exim on my server, via ppardis.

@Talman:

This is easy. Linode Library has a exim-based solution, you need a "send only" mail server.

You can also install postfix and set it to loopback-only, I believe. I use exim on my server, via ppardis.
As in this? http://library.linode.com/email/exim/se … 0.04-lucid">http://library.linode.com/email/exim/send-only-mta-ubuntu-10.04-lucid

Postfix should work fine, automatically with Drupal. And you definitely need to make sure you have a working MTA for all sorts of server admin tasks.

But you might also consider using the PHPMailer module for Drupal.http://drupal.org/project/phpmailer PHPMailer is a separate PHP library which will let Drupal connect securely to your gmail account and use gmail's servers to send your mail.

Advantages include saving copies of sent messages on Google's servers, use of both SPF and (since last week) DKIM for anti-spam so your emails don't get flagged as spam, and your emails look like they come from your domain and not the RDNS or hostname of the server.

Major disadvantage is that Google only allows 500 emails per day.

You can also set up Postfix to send mail through Google (or another relay of your choosing) using client SASL. On Ubuntu, I think Postfix is already linked with the Cyrus library so it should just be a matter of setting up the configuration. Searching for gmail and postfix will get you several articles.

Thanks for the suggestions! This http://library.linode.com/email/exim/se … 0.04-lucid">http://library.linode.com/email/exim/send-only-mta-ubuntu-10.04-lucid worked great for me. I'll the keep the other ideas in mind for if they are needed in the future.