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Allow or block IPv6 addresses using the Tenant Allow/Block List

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In Microsoft 365 organizations with mailboxes in Exchange Online or standalone Exchange Online Protection (EOP) organizations without Exchange Online mailboxes, admins can create and manage entries for IPv6 addresses in the Tenant Allow/Block List. For more information about the Tenant Allow/Block List, see Manage allows and blocks in the Tenant Allow/Block List.

This article describes how admins can manage entries for IPv6 addresses in the Microsoft Defender portal and in Exchange Online PowerShell.

What do you need to know before you begin?

  • You open the Microsoft Defender portal at https://security.microsoft.com. To go directly to the Tenant Allow/Block Lists page, use https://security.microsoft.com/tenantAllowBlockList. To go directly to the Submissions page, use https://security.microsoft.com/reportsubmission.

  • To connect to Exchange Online PowerShell, see Connect to Exchange Online PowerShell. To connect to standalone EOP PowerShell, see Connect to Exchange Online Protection PowerShell.

  • IPv6 addresses are supported only in the following formats:

    • Single addresses in colon-hexadecimal format. For example, 2001:0db8:85a3:0000:0000:8a2e:0370:7334.
    • Single addresses in zero-compression format. For example, 2001:db8::1 represents 2001:0db8:0000:0000:0000:0000:0000:0001.
    • CIDR IPv6 range. For example, 2001:0db8::/32. 1-128 range is supported.

  • Entry limits for IP addresses:

    • Exchange Online Protection: The maximum number of allow entries is 500, and the maximum number of block entries is 500 (1000 IP entries in total).
    • Defender for Office 365 Plan 1: The maximum number of allow entries is 1000, and the maximum number of block entries is 1000 (2000 IP entries in total).
    • Defender for Office 365 Plan 2: The maximum number of allow entries is 5000, and the maximum number of block entries is 10000 (15000 IP entries in total).

  • An entry should be active within 5 minutes.

  • You need to be assigned permissions before you can do the procedures in this article. You have the following options:

    • Microsoft Defender XDR Unified role based access control (RBAC) (If Email & collaboration > Exchange Online permissions permissions is Active. Affects the Defender portal only, not PowerShell): Authorization and settings/Security settings/Detection tuning (manage) or Authorization and settings/Security settings/Core security settings (read).

    • Exchange Online permissions:

      • Add and remove entries from the Tenant Allow/Block List: Membership in one of the following role groups:
        • Organization Management or Security Administrator (Security admin role).
        • Security Operator (Tenant AllowBlockList Manager role): This permission works only when assigned directly in the Exchange admin center at https://admin.exchange.microsoft.com > Roles > Admin Roles.
      • Read-only access to the Tenant Allow/Block List: Membership in one of the following role groups:
        • Global Reader
        • Security Reader
        • View-Only Configuration
        • View-Only Organization Management

    • Microsoft Entra permissions: Membership in the Global Administrator*, Security Administrator, Global Reader, or Security Reader roles gives users the required permissions and permissions for other features in Microsoft 365.

      Important

      * Microsoft recommends that you use roles with the fewest permissions. Using lower permissioned accounts helps improve security for your organization. Global Administrator is a highly privileged role that should be limited to emergency scenarios when you can't use an existing role.

Create allow entries for IPv6 addresses

The allow entry overrides only the IP filters for the specified sending IP address.

You can create allow entries for IPv6 addresses directly in the Tenant Allow/Block List as described in this section.

Use the Microsoft Defender portal to create allow entries for IPv6 addresses in the Tenant Allow/Block List

  1. In the Microsoft Defender portal at https://security.microsoft.com, go to Policies & rules > Threat Policies > Rules section > Tenant Allow/Block Lists. Or, to go directly to the Tenant Allow/Block Lists page, use https://security.microsoft.com/tenantAllowBlockList.

  2. On the Tenant Allow/Block Lists page, select the IP addresses tab.

  3. On the IP addresses tab, select Allow.

  4. In the Allow IP addresses flyout that opens, configure the following settings:

    • Add IP address: Enter one IP address per line, up to a maximum of 20.

    • Remove allow entry after: Select from the following values:

      • 1 day
      • 7 days
      • 30 days
      • Never expire (default)
      • Specific date: The maximum value is 90 days from today.

    • Optional note: Enter descriptive text for why you're allowing the IP addresses.

    When you're finished in the Allow IP addresses flyout, select Add.

Back on the IP addresses tab, the entry is listed.

Use PowerShell to create allow entries for IPv6 addresses in the Tenant Allow/Block List

In Exchange Online PowerShell, use the following syntax:

New-TenantAllowBlockListItems -ListType IP -Allow -Entries "IPAddress1","IPAddress2",..."IPAddressN" <-ExpirationDate Date | -NoExpiration> [-Notes <String>]

This example adds an allow entry for the specified IP address that never expires.

New-TenantAllowBlockListItems -ListType IP -Allow -Entries "2001:db8:3333:4444:5555:6666:7777:8882" -NoExpiration

For detailed syntax and parameter information, see New-TenantAllowBlockListItems.

Create block entries for IPv6 addresses

You can create block entries for IPv6 addresses directly in the Tenant Allow/Block List as described in this section.

Incoming email messages from IPv6 addresses in block entries are blocked at the edge of the service.

Use the Microsoft Defender portal to create block entries for IPv6 addresses in the Tenant Allow/Block List

  1. In the Microsoft Defender portal at https://security.microsoft.com, go to Policies & rules > Threat Policies > Rules section > Tenant Allow/Block Lists. Or, to go directly to the Tenant Allow/Block Lists page, use https://security.microsoft.com/tenantAllowBlockList.

  2. On the Tenant Allow/Block Lists page, select the IP addresses tab.

  3. On the IP addresses tab, select Block.

  4. In the Block IP addresses flyout that opens, configure the following settings:

    • Add IP address: Enter one IP address per line, up to a maximum of 20.

    • Remove block entry after: Select from the following values:

      • 1 day
      • 7 days
      • 30 days
      • Never expire (default)
      • Specific date: The maximum value is 90 days from today.

    • Optional note: Enter descriptive text for why you're blocking the IP addresses.

    When you're finished in the Block IP addresses flyout, select Add.

Back on the IP addresses tab, the entry is listed.

Use PowerShell to create block entries for IPv6 addresses in the Tenant Allow/Block List

In Exchange Online PowerShell, use the following syntax:

New-TenantAllowBlockListItems -ListType IP -Block -Entries "IPAddress1","IPAddress2",..."IPAddressN" <-ExpirationDate Date | -NoExpiration> [-Notes <String>]

This example adds an block entry for the specified IP address that never expires.

New-TenantAllowBlockListItems -ListType IP -Block -Entries "2001:db8:3333:4444:5555:6666:7777:8882" -NoExpiration

For detailed syntax and parameter information, see New-TenantAllowBlockListItems.

Use the Microsoft Defender portal to view entries for IPv6 addresses in the Tenant Allow/Block List

In the Microsoft Defender portal at https://security.microsoft.com, go to Policies & rules > Threat Policies > Tenant Allow/Block Lists in the Rules section. Or, to go directly to the Tenant Allow/Block Lists page, use https://security.microsoft.com/tenantAllowBlockList.

Select the IP addresses tab.

On the IP addresses tab, you can sort the entries by clicking on an available column header. The following columns are available:

  • Value: The IP address.
  • Action: The available values are Allow or Block.
  • Modified by
  • Last updated
  • Last used date: The date the entry was last used in the filtering system to override the verdict.
  • Remove on: The expiration date.
  • Notes

To filter the entries, select Filter. The following filters are available in the Filter flyout that opens:

  • Action: The available values are Allow and Block.
  • Never expire: or
  • Last updated: Select From and To dates.
  • Last used date: Select From and To dates.
  • Remove on: Select From and To dates.

When you're finished in the Filter flyout, select Apply. To clear the filters, select Clear filters.

Use the Search box and a corresponding value to find specific entries.

To group the entries, select Group and then select Action. To ungroup the entries, select None.

Use PowerShell to view entries for IPv6 addresses in the Tenant Allow/Block List

In Exchange Online PowerShell, use the following syntax:

Get-TenantAllowBlockListItems -ListType IP [-Allow] [-Block] [-Entry <IPaddress>] [<-ExpirationDate Date | -NoExpiration>]

This example returns all allowed and blocked IP addresses.

Get-TenantAllowBlockListItems -ListType IP

This example returns information for the specified IP address.

Get-TenantAllowBlockListItems -ListType IP -Entry "2001:db8:3333:4444:5555:6666:7777:8882"

This example filters the results by blocked IP address.

Get-TenantAllowBlockListItems -ListType IP -Block

For detailed syntax and parameter information, see Get-TenantAllowBlockListItems.

Use the Microsoft Defender portal to modify entries for IPv6 addresses in the Tenant Allow/Block List

For existing IP addresses entries, you can change the expiration date and note.

  1. In the Microsoft Defender portal at https://security.microsoft.com, go to Policies & rules > Threat Policies > Rules section > Tenant Allow/Block Lists. Or, to go directly to the Tenant Allow/Block Lists page, use https://security.microsoft.com/tenantAllowBlockList.

  2. Select the IP addresses tab

  3. On the IP addresses tab, select the entry from the list by selecting the check box next to the first column, and then select the Edit action that appears.

  4. In the Edit IP addresses flyout that opens, the following settings are available:

    • Block entries:
      • Remove block entry after: Select from the following values:
        • 1 day
        • 7 days
        • 30 days
        • Never expire
        • Specific date: The maximum value is 90 days from today.
      • Optional note
    • Allow entries:
      • Remove allow entry after: Select from the following values:
        • 1 day
        • 7 days
        • 30 days
        • Never expire
        • Specific date: The maximum value is 30 days from today.
      • Optional note

    When you're finished in the Edit IP addresses flyout, select Save.

Use PowerShell to modify existing allow or block entries for IPv6 addresses in the Tenant Allow/Block List

In Exchange Online PowerShell, use the following syntax:

Set-TenantAllowBlockListItems -ListType IP <-Ids <Identity value> | -Entries <Value> [<-ExpirationDate Date | -NoExpiration>] [-Notes <String>]

This example changes the expiration date of the specified IP address block entry.

Set-TenantAllowBlockListItems -ListType IP -Entries "2001:db8:3333:4444:5555:6666:7777:8882" -ExpirationDate "9/1/2024"

For detailed syntax and parameter information, see Set-TenantAllowBlockListItems.

Use the Microsoft Defender portal to remove entries for IPv6 addresses from the Tenant Allow/Block List

  1. In the Microsoft Defender portal at https://security.microsoft.com, go to Policies & rules > Threat Policies > Rules section > Tenant Allow/Block Lists. Or, to go directly to the Tenant Allow/Block Lists page, use https://security.microsoft.com/tenantAllowBlockList.

  2. Select the IP addresses tab.

  3. On the IP addresses tab, do one of the following steps:

    • Select the entry from the list by selecting the check box next to the first column, and then select the Delete action that appears.

    • Select the entry from the list by clicking anywhere in the row other than the check box. In the details flyout that opens, select Delete at the top of the flyout.

      Tip

      To see details about other entries without leaving the details flyout, use Previous item and Next item at the top of the flyout.

  4. In the warning dialog that opens, select Delete.

Back on the IP addresses tab, the entry is no longer listed.

Tip

You can select multiple entries by selecting each check box, or select all entries by selecting the check box next to the Value column header.

Use PowerShell to remove entries for IPv6 addresses from the Tenant Allow/Block List

In Exchange Online PowerShell, use the following syntax:

Remove-TenantAllowBlockListItems -ListType IP <-Ids <Identity value> | -Entries <Value>>

This example removes the specified IP address block from the Tenant Allow/Block List.

Remove-TenantAllowBlockListItems -ListType IP -Entries "2001:db8:3333:4444:5555:6666:7777:8882"

For detailed syntax and parameter information, see Remove-TenantAllowBlockListItems.