How SMG determines the direction (Inbound or Outbound) of an email

Products

• Messaging Gateway

Issue/Introduction

When a device or system uses SMG as a relay to send messages only to internal recipients, the messages are marked with Outbound direction which triggers an unnecessary check.

Environment

SMG 10.8 10.9

Resolution

The classification logic on the Scanner is based on the IP address from which the email is received:

• SMG checks the sending IP against the lists configured under:
  Administration > Configuration > Edit Host > SMTP > Inbound Mail Acceptance
  Administration > Configuration > Edit Host > SMTP > Outbound Mail Acceptance

• If the sending IP is listed under Outbound Mail Acceptance, SMG treats the message as Outbound.

• If the IP is not on the outbound list and Inbound Mail Acceptance is set to accept inbound mail connections from all IP address and domains, SMG classifies the message as Inbound.

This is how SMG decides how to process and apply policy rules to the message. If your devices' IPs are listed in the Outbound Acceptance list, they will always be treated as sending outbound mail—even if all recipients are internal.