Commands › Exchange Online

New-X400AuthoritativeDomain

Exchange Online ExchangeOnlineManagement New-*

Create and specify the X.400 authoritative domain for the organization. The X.400 authoritative domain defines the standard fields for the namespace appended to the recipient identity for all mailboxes assigned an X.400 address.

Quick start script

# New-X400AuthoritativeDomain — quick start (serv365.ai)
# 1. Connect (app-only shown; interactive: omit the certificate parameters)
Connect-ExchangeOnline -CertificateThumbprint $thumb -AppId $appId -Organization $org

# 2. Capture the current state first — you cannot roll back what you never recorded
$before = Get-X400AuthoritativeDomain
$before | Format-List

# 3. Make the change (dry run first)
New-X400AuthoritativeDomain -Name <String> -X400DomainName <X400Domain> -WhatIf
New-X400AuthoritativeDomain -Name <String> -X400DomainName <X400Domain>

# 4. Verify and diff
$after = Get-X400AuthoritativeDomain
Compare-Object ($before | Out-String) ($after | Out-String)

Syntax

New-X400AuthoritativeDomain [-Name] <String> -X400DomainName <X400Domain>
 [-Confirm]
 [-DomainController <Fqdn>]
 [-WhatIf]
 [-X400ExternalRelay <Boolean>]
 [<CommonParameters>]

Parameters (6)

Parameter	Type	Required	What it controls
-Name	String	yes	The Name parameter specifies the unique name for the X.400 authoritative domain. The maximum length is 64 characters. If the value contains spaces, enclose the value in quotation marks (").
-X400DomainName	X400Domain	yes	The X400DomainName parameter specifies the X.400 namespace, which can only include the X.400 organizational components. Specifically, only the following attribute types are supported:
-Confirm	SwitchParameter		The Confirm switch specifies whether to show or hide the confirmation prompt. How this switch affects the cmdlet depends on whether the cmdlet requires confirmation before proceeding.
-DomainController	Fqdn		The DomainController parameter specifies the domain controller that's used by this cmdlet to read data from or write data to Active Directory. You identify the domain controller by its fully qualified domain name...
-WhatIf	SwitchParameter		The WhatIf switch shows what the command does without making any changes. You don't need to specify a value with this switch.
-X400ExternalRelay	Boolean		The X400ExternalRelay parameter specifies authoritative domain an external relay domain. If you set the X400ExternalRelay parameter to $true, Microsoft Exchange routes email to the external address and doesn't treat...

Reference facts derived from Microsoft documentation, © Microsoft, licensed CC BY 4.0; restructured with original guidance by serv365.ai.