Undelivery report --sender: Postmaster@domain.com

Exchange Management Shell

get-remotedomain | fl

DomainName : *
CharacterSet : iso-8859-1
NonMimeCharacterSet : iso-8859-1
AllowedOOFType : External
AutoReplyEnabled : False
AutoForwardEnabled : False
DeliveryReportEnabled : True
NDREnabled : True
MeetingForwardNotificationEnabled : False
ContentType : MimeHtmlText
DisplaySenderName : True
TNEFEnabled :
LineWrapSize : unlimited
UseSimpleDisplayName : False
AdminDisplayName :
ExchangeVersion : 0.1 (8.0.535.0)

set-remotedomain Default -NDREnabled $false

get-remotedomain | fl

DomainName : *
CharacterSet : iso-8859-1
NonMimeCharacterSet : iso-8859-1
AllowedOOFType : External
AutoReplyEnabled : False
AutoForwardEnabled : False
DeliveryReportEnabled : True
NDREnabled : False
MeetingForwardNotificationEnabled : False
ContentType : MimeHtmlText
DisplaySenderName : True
TNEFEnabled :
LineWrapSize : unlimited
UseSimpleDisplayName : False
AdminDisplayName :
ExchangeVersion : 0.1 (8.0.535.0)

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Install Antispam package

Recipient Filtering--Block messages sent to recipients not listed in the Global Address List