Bypass 3rd Party filters with Receive Connector
Introduction
This document provides step-by-step instructions for configuring a secure mail flow connector in Office 365 to ensure reliable email delivery from SUCURILABS - CYBERHOOK while bypassing third-party filtering systems.
Why does SUCURILABS recommend a Receive Connector?
To bypass third-party systems in some scenarios Cyberhook may need to bypass additional filtering systems (e.g. email scanners) that might affect normal mail flow to your mail server. Receive Connector is a feature that makes it possible for Cyberhook to send simulation emails directly to your email system (e.g. M365 or on-premise Exchange). Receive Connector is always recommended for hybrid environments to minimise mail flow issues.
Warning
Although it's possible to bypass many filter systems with allowlisting, SUCURILABS strongly recommends to configure a Receive Connector. Some filter vendors won't guarantee 100% deliverability for Cyberhook training emails due to the filter system's design principles.

Step 1: Create the Partner Receive Connector
1. Access the Exchange Admin Center
- Log in to Microsoft 365 Admin Center
- Navigate to:
Exchange Admin Center > Mail Flow > Connectors - Click + Add a connector

- In New Connector screen, select Partner organization and click Next.

- In Connector name screen, provide a name for your Cyberhook connector.
- Under What do you want to do after the connector is saved?, tick Turn it on and click Next.

- In Authenticating sent email screen, select the second option to authenticate by sender IP address.
- Add the following IP addresses separately, and click + button to add them to the list below.
- 51.178.182.159
- Click Next.

- Under Security restrictions screen, use the default values (see screenshot) and click Next.

- Under Review connector screen, verify the configuration is correct and click Create connector.
You have now successfully configured Cyberhook Receive Connector.
Step 2: Note Your Default MX Record for your tenant/domains
- Go to Microsoft 365 Admin Center > Settings > Domains
- Select your default domain

- Navigate to DNS records tab
- Locate your MX record (typically ends with
.mail.protection.outlook.com) - Record this value for reference
Example
Your registered public domain name is company.com
Your M365 tenant's MX record is company-com.mail.protection.outlook.com