Whitelisting IP Addresses via Connection Filter Policy in Exchange Online (Microsoft Defender)

ExSign Email Signatures for Microsoft Exchange Server
Purpose
This article provides step-by-step instructions on how to add trusted IP addresses to the Connection Filter Policy (Default) in Microsoft Defender for Office 365. This is useful for allowing specific IPs to bypass spam filtering in Exchange Online.

Prerequisites
  • You must have Global Administrator or Security Administrator privileges in Microsoft 365.
Steps to Add IPs to Connection Filter Policy

1. Sign in to Microsoft 365 Admin Center
2. Navigate to Microsoft Defender
  • In the left-hand navigation pane, click “Show all” (if needed).
  • Click Security to open the Microsoft 365 Defender portal.
     This will redirect you to: https://security.microsoft.com


3. Open Policies & Rules
  • In the left menu, expand Email & collaboration.
  • Click Policies & rules.


4. Access Threat Policies
  • Under Policies & rules, click Threat policies.


5. Open Anti-Spam Settings
  • Click Anti-spam from the list of available threat policies.


6. Modify the Connection Filter Policy
  • Scroll down and click Connection filter policy (Default).
  • In the policy settings, locate the section to add IP addresses.
  • Enter the trusted IP addresses (ExSign Agent IP)  you wish to allow.


7. Save Changes
  • After adding your IP addresses, click Save to apply the changes.
Result
The specified IP addresses are now part of your trusted list and will bypass spam filtering as defined in the Connection Filter Policy.

Additional Notes
  • Changes may take a few minutes to take effect.
  • Be cautious when adding IPs to ensure you're not allowing potentially harmful sources.
 
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Article ID: 3474, , Modified: 5/16/2025 at 7:18 AM

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