Knowledgebase: Inbound Mail Flow
How to configure inbound relaying on Office 365
Posted by Vinh N, Last modified by Joseph O'Donnell on 11 October 2018 07:34 AM
Situation The following steps should be taken to route email from Proofpoint Essentials to Office 365.  These steps will help you provision/setup mail-flow for the first time.
  1. Configure Proofpoint Essentials
  2. Register domain with Proofpoint Essentials

1) Configure Proofpoint Essentials

Locate your MX record for your domain in Office 365

  1. Log in to the Office 365 Admin Center
  2. Click on Setup from the left side navigation panel
  3. Click on Domains 
  4. Select the domain you wish to manage
  5. Under Exchange Online, locate the MX row in the table (under the Points to address column)
  6. Keep this information readily accessible


2) Register domain with Proofpoint Essentials

  1. Log in to Proofpoint Essentials
  2. Click on the Domains tab
  3. Click on Add New Domain
  4. Enter your domain name
  5. Select purpose (Relay)
  6. Copy the MX row value from the Points to address column in the Office 365 admin portal located previously
  7. Click Save



Bypassing Spam Filtering in Office 365

You may want to adjust your spam filtering policy in Office 365 to bypass filtering for clean mail that is being sent from Proofpoint Essentials. Proofpoint Essentials IP ranges should be added to the Allowed List in the Connection Filtering Policy within the Office 365 Exchange Admin Center.

To add Proofpoint Essentials IP Ranges to the Connection Filter Policy:

  1. Log in to the Office 365 Exchange Admin Center (EAC)
  2. Click on protection
  3. Click on connection filter
  4. Click the Edit icon
  5. Click on connection filtering
  6. Click on the plus icon +within the IP Allow list section
  7. Add the Proofpoint Essentials Main IP Address for the Data Center your account is located on. These IP addresses can be found at the following link:
  8. Tick checkbox Enable safe list
  9. Click Save to apply changes


Add a mail flow rule to allow email to be sent from Proofpoint Essentials

  1. While accessing the Exchange Admin Center, click mail flow then rules.
  2. Click + to access the pull down menu.
  3. Select Restrict messages by sender or recipient…
  4. In the new rule window, complete the required fields:
    1. Enter a value for Name (for example, Enter Only accept mail from Proofpoint)
    2. For Apply this rule if… select The Sender is located… and Outside the organization.
    3. For Do the following… select Redirect the message to and choose your Admin's email address.
    4. Uncheck Audit this rule with severity level.
    5. For Choose a mode for this rule select Enforce.
    6. Click More options.
    7. Click add exception.
    8. Select the sender... > IP address is in any of these ranges or exactly matches
    9. Add each IP address to the IP address list.
  5. Click OK
  6. Clive Save.
  7. Uncheck the checkbox to disable the rule. You will re-enable the rule once you are ready to cutover mailflow


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