How to set Microsoft Exchange 2013 to mark off-domain Emails as spam

We’re getting emails with “” or “”, but do not have no-reply as a mailbox. Is there a way to say anyone without a mailbox with our domain reject as junk or spam? I am currently running Microsoft Exchange 2013 and have Symantec Mail security for exchange running, but it still seems like there’s a lot of invalid emails getting through. I know in previous version I saw there seemed to be a more clear way of doing this.


I think you want the following

Set-RecipientFilterConfig -Enabled $true

To enable filtering, then

Set-RecipientFilterConfig -RecipientValidationEnabled $true

To drop anything for an email address that doesn’t exist.

*If this is on a server that doesn’t include the edge server role you will need to install the agents with the following command

& $env:ExchangeInstallPathScriptsInstall-AntiSpamAgents.ps1