Set-ArcConfig

Reference

Module:: ExchangePowerShell

Applies to:: Exchange Online, Exchange Online Protection

This cmdlet is available only in the cloud-based service.

Use the Set-ArcConfig cmdlet to modify the list of trusted Authenticated Received Chain (ARC) sealers that are configured in the cloud-based organization.

For information about the parameter sets in the Syntax section below, see Exchange cmdlet syntax.

Syntax

Set-ArcConfig
   [-Identity] <HostedConnectionFilterPolicyIdParameter>
   -ArcTrustedSealers <String[]>
   [-Confirm]
   [-WhatIf]
   [<CommonParameters>]

Description

Services that modify message content in transit before delivery can invalidate DKIM email signatures and affect the authentication of the message. These services can use ARC to provide details of the original authentication before the modifications occurred. Your organization can then trust these details to help authenticate the message.

You need to be assigned permissions before you can run this cmdlet. Although this topic lists all parameters for the cmdlet, you may not have access to some parameters if they're not included in the permissions assigned to you. To find the permissions required to run any cmdlet or parameter in your organization, see Find the permissions required to run any Exchange cmdlet.

Examples

Example 1

Set-ArcConfig -Identity Default -ArcTrustedSealers fabrikam.com

This example configures "fabrikam.com" as the only trusted ARC sealer in the organization.

Example 2

$DomainsAdd = @(Get-ArcConfig | select -Expand ArcTrustedSealers)

$DomainsAdd += "cohovineyard.com","tailspintoys.com"

Set-ArcConfig -Identity Default -ArcTrustedSealers $DomainsAdd

This example adds the trusted ARC sealers "cohovineyard.com" and "tailspintoys.com" without affecting the other trusted ARC sealer entries.

Example 3

$x = @(Get-ArcConfig | select -Expand ArcTrustedSealers)

$y = $x.Split(",")

$DomainsRemove = [System.Collections.ArrayList]($y)

$DomainsRemove

$DomainsRemove.RemoveAt(6)

Set-ArcConfig -Identity Default -ArcTrustedSealers $DomainsRemove

This example modifies the trusted ARC sealers list by removing an existing ARC sealer without affecting other ARC sealers that are already specified.

The first four commands return the existing list of ARC sealers. The first ARC sealer in the list has the index number 0, the second has the index number 1, and so on. Use the index number to specify the ARC sealer that you want to remove.

The last two commands remove the seventh ARC sealer that's displayed in the list.

Parameters

-ArcTrustedSealers

The ArcTrustedSealers parameter specifies the domain name of the ARC sealers that you want to add.

The domain name must match the domain that's shown in the d tag in the ARC-Seal and ARC-Message-Signature headers in affected email messages (for example, fabrikam.com). You can use Outlook to see these headers.

To replace the existing list of ARC sealers with the values you specify, use the syntax Domain1,Domain2,...DomainN. To preserve existing values, be sure to include the file types that you want to keep along with the new values that you want to add.

To add or remove file types without affecting the other file type entries, see the Examples section in this topic.

Type:	String[]
Position:	Named
Default value:	None
Required:	True
Accept pipeline input:	False
Accept wildcard characters:	False
Applies to:	Exchange Online, Exchange Online Protection

-Confirm

The Confirm switch specifies whether to show or hide the confirmation prompt. How this switch affects the cmdlet depends on if the cmdlet requires confirmation before proceeding.

Destructive cmdlets (for example, Remove-* cmdlets) have a built-in pause that forces you to acknowledge the command before proceeding. For these cmdlets, you can skip the confirmation prompt by using this exact syntax: -Confirm:$false.
Most other cmdlets (for example, New-* and Set-* cmdlets) don't have a built-in pause. For these cmdlets, specifying the Confirm switch without a value introduces a pause that forces you acknowledge the command before proceeding.

Type:	SwitchParameter
Aliases:	cf
Position:	Named
Default value:	None
Required:	False
Accept pipeline input:	False
Accept wildcard characters:	False
Applies to:	Exchange Online, Exchange Online Protection

-Identity

The Identity parameter specifies the trusted ARC sealers list that you want to modify. Use one of the following values:

Default for your own organization.
<TenantID>\Default for delegated organizations. The <TenantID> value is a GUID that's visible in many admin portal URLs in Microsoft 365 (the tid= value). For example, a32d39e2-3702-4ff5-9628-31358774c091.

Type:	HostedConnectionFilterPolicyIdParameter
Position:	1
Default value:	None
Required:	True
Accept pipeline input:	True
Accept wildcard characters:	False
Applies to:	Exchange Online, Exchange Online Protection

-WhatIf

The WhatIf switch simulates the actions of the command. You can use this switch to view the changes that would occur without actually applying those changes. You don't need to specify a value with this switch.

Type:	SwitchParameter
Aliases:	wi
Position:	Named
Default value:	None
Required:	False
Accept pipeline input:	False
Accept wildcard characters:	False
Applies to:	Exchange Online, Exchange Online Protection