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IPv6 is not enabled by default in the Microsoft 365 tenant for Exchange Online. You like to configure inbound email in Exchange Online to support IPv6. There is also no option right now to enable it. But does that mean it’s not possible? In this article, you will learn how to enable IPv6 for Exchange Online in Microsoft 365.

Point MX record to Exchange Online

Ensure that you update MX records to Exchange Online before you start.

Check Exchange Online IPv6 inbound status

To check Exchange Online IPv6 inbound status, follow these steps:

  • Go to MXToolBox
  • Fill in the domain
  • Click on MX Lookup

The below screenshot shows that the Exchange Online MX record is added but can’t resolve to IPv6 and only resolves to the IPv4 address.

Note: If IPv6 support is enabled, you will see two IP addresses for Exchange Online. One IPv4 and one IPv6 address.

Enable IPv6 in Exchange Online MXToolBox

Another way to test is with the SMTP Email Test Tool:

Enable IPv6 in Exchange Online SMTP email test tool

The below screenshot shows that the Exchange Online MX record is added but can’t resolve to IPv6 and only resolves to the IPv4 address.

Enable IPv6 in Exchange Online couldn't resolve address

Let’s look at the next step of enabling IPv6 in Exchange Online.

Add Exchange Online IPv6 inbound support

Before your organization can receive anonymous inbound email over IPv6, an admin needs to contact Microsoft support and ask for it.

Create a service request in Microsoft 365 admin center:

Microsoft 365 Help & Support
  • Type Enable IPv6
  • Press Enter
  • Click on Contact support
Enable IPv6 in Exchange Online how can we help
  • Fill out the support ticket
  • Click Contact me

Note: You can specify which domain you want to enable IPv6 for in Exchange Online.

Enable IPv6 in Exchange Online contact support

Wait for Microsoft to enable IPv6 for the domain in Exchange Online and send you a confirmation.

Verify Exchange Online IPv6 inbound status

To verify Exchange Online IPv6 inbound status with MXToolBox, follow these steps:

  • Go to MXToolBox
  • Fill in the domain
  • Click on MX Lookup

The below screenshot shows that the Exchange Online MX record is added and resolves both to IPv4 and IPv6 addresses.

Enable IPv6 in Exchange Online verify MXToolBox

To verify Exchange Online IPv6 inbound status with SMTP Email Test Tool, follow these steps:

SMTP email test tool enter domain

The below screenshot shows that the Exchange Online MX record is added and resolves both to IPv4 and IPv6 addresses.

Enable IPv6 in Exchange Online verify SMTP email test tool

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