• Article

MailUser.ImmutableId Property

Gets or sets the unique and immutable identifier (ID) in the form of a Simple Mail Transfer Protocol (SMTP) address for a user’s mailbox that is used for federated delegation when requesting Security Assertion Markup Language (SAML) tokens.

Namespace:  Microsoft.Exchange.Data.Directory.Management
Assembly:  Microsoft.Exchange.Data.Directory (in Microsoft.Exchange.Data.Directory.dll)

Syntax

'Declaration
<ParameterAttribute(Mandatory := False)> _
Public Property ImmutableId As String
    Get
    Set
'Usage
Dim instance As MailUser
Dim value As String

value = instance.ImmutableId

instance.ImmutableId = value

[ParameterAttribute(Mandatory = false)]
public string ImmutableId { get; set; }

Property Value

Type: System.String
The unique and immutable ID.

Remarks

If the federation is configured for this user’s mailbox and this property is not set when the mailbox is created, Microsoft Exchange Server creates the value for the immutable ID based upon the ExchangeGuid of the mailbox and the federated account namespace. This property must bet set if Active Directory Federation Services (AD FS) is deployed to allow single sign-on into off-premises (federated) mailboxes and AD FS is configured to use a different attribute than ExchangeGuid for sign-on token requests.