Approved Domain doesn't work for subdomains under Email Impersonation Control (EIC)

Products

• Email Security.cloud

Issue/Introduction

When a user adds a domain to the Approved Senders in Email Impersonation Control, an email coming from a subdomain of that entry is still caught by Email Impersonation Control ( EIC ).

Environment

Email Impersonation Control

Cause

The Approved Senders lists for Anti-Spam and Email Impersonation Control (EIC) are distinct and operate independently. While adding a domain to the Anti-Spam Approved Sender list will also approve any subdomains of the listed domain; the EIC Approved Senders list only approves the parent domain and not to its subdomains.

Resolution

Email Impersonation Control service uses exact match for the Envelope Sender domain. If sub-domain is required to be part of the approved entries, a wildcarded entry has to be added.  

Here's an example explanation:

1. If a user adds " example.com " to the Approved Sender Domains in Email Impersonation Control, it allows bypassing EIC for all emails from "example.com".
2. If the user adds " *.example.com " to the Approved Sender Domains in Email Impersonation Control, it allows bypassing EIC for all emails from subdomains of "example.com" .