Do Google Apps SMTP servers automatically sign messages with DKIM?

Question

I've configured my Google Apps account to sign messages with my DomainKey (DKIM), and I've confirmed that the signing takes place and works correctly when I send mail directly from my Google Apps account.

Now, I want to combine that with my web applications that send email through the same domain using Google's SMTP servers. Here's the only issue I see: do Google's SMTP servers automatically sign the messages I programmatically send from my Google Apps account with DKIM, or do I have to do that manually?

Answer 1

My testing has revealed that they do automatically sign messages that are sent through their SMTP servers.