Google Compute Engine (GCE) email delivery solution?

Question

I've just setup several instances on Google Compute Engine and getting trouble with email delivery system since GCE blocks outbound connections on ports 25, 465, and 587.

GCE provides details solution at: https://developers.google.com/compute/docs/networking#mailserver to using postfix to send email via smtp.gmail.com using Google Account.

The problem is Gmail has its own sending limits and it will be a big problem for high traffic website which need to send email notifications heavily.

Is there anyone has a solution to send more higher sending limits for GCE instances?

Thanks in advance. Best Regards, T

Answer 1

Your best option is to sign up for Amazon SES and get the API credentials and endpoint to send mail from google cloud without any google limitations.

You can use any similar API as well.

Answer 2

From the same page:

Blocked Traffic

Traffic on these ports to and from the Internet are blocked or restricted for all Google Compute Engine instances. If you think you have a compelling reason to allow this traffic, please contact the Google Compute Engine team at [email protected].

• All outgoing traffic to port 25 (SMTP) is blocked
• Most outgoing traffic to port 465 or 587 (SMTP over SSL) is blocked except for known Google IP addresses

https://developers.google.com/compute/docs/networking#blockedtraffic

It looks like you'll need to have a compelling reason to allow the traffic for your application; I'm presuming that hitting GMail delivery limits might be a reason. Note that companies like SendGrid also offer email delivery and management (bulk email as a service) with an HTTP interface that you could call from GCE.