Multiple Server Email Configuration Without Spam Blocking?
My company uses multiple servers (some Linux, some Windows) to run our software. The servers are not in the same location and they do not all run the same software. But, we need to be able to send emails from code running on each of these servers. (I'm not incredibly worried about the Windows ones at this time. Just the Linux ones.)
We no longer handle company email in-house. After months of fighting with Zimbra to get it to work properly, we ended up letting google for our domain handle our incoming emails. And, when we send emails through our email clients, we use gmail's smtp servers. No problem there.
The problem is that google's smtp servers are way too slow for us to use when the code sends emails. For that, I would prefer to use postfix, sendmail, dovecot or whatever is on the individual server.
Getting the servers configured to send email is also not a problem. Each server can send emails. What is the problem is that the emails from these servers gets blocked as spam.
What is the proper way for me to configure these servers so that even though our MX records for our domain point to google, that we can use our own sending capabilities and have the world recognize mail coming from these servers as coming from us? Each sever will host numerous subdomains that emails will come from.
Another thought - is there any way to use a mail server of some sort on each server to queue up emails and send them through our google smtp account so that the code could 'send' the email to that queue and return and then the server could funnel it through google as fast or as slow as google could handle it?
At some point, I will rewrite the code on some of the applications to put the emails in an outgoing queue instead of trying to send them directly. But, even so, I would dearly love to get this problem resolved so that we can quickly send out emails from our applications.