Google Message Security Troubleshooting Guide - Manual (Page 55)

Mail Flow Troubleshooting 57
Mail Flow Troubleshooting
Chapter 2
Mail Flow
Why am I not getting any mail at all?
Follow these steps to find out why you can’t receive mail from any outside sender.
Stages of Mail Flow
Before you begin troubleshooting mail flow, be sure you understand how
messages normally flow from a sender to your server through the message
security service. Then you can find out at what stage the failure is occurring.
This graph shows the normal steps of mail flow:
1. The sender connects to the email security service and sends the message.
2. The email security service filters the message for spam, viruses, content and
attachments.
3. The email security service sends the message to the recipient server.
4. The recipient server delivers mail to the user.