When you send an email message, the recipient can view the headers of the message and see all of the “hops” that the message went through on its journey from one mailbox to another.
The header info is very useful in troubleshooting situations, because you can copy/paste it into tools like the message analyzer in the Microsoft Remote Connectivity Analyzer and look at things like delays in message transfer between servers along the route the message took.
However, some organizations don’t want their internal Exchange server names and IP addresses exposed in the message headers of emails sent outside of their organization. To remove them, you can use a feature called the header firewall, which is explained in detail on TechNet.
The first step is to determine the name of your outbound send connector for internet email. In my environment an Edge Transport server is used for outbound mail, so the outbound send connector is named “EdgeSync – Datacenter1 to Internet” (Datacenter1 is the name of the Active Directory site the Edge server is subscribed to). I want to remove the message headers for outbound mail sent over that connnector only, and not impact the messages sent over other connectors to Office 365 or the Globomantics partner organization.
The command to remove the message headers is as follows:
|[PS] C:\>Get-SendConnector “EdgeSync – Datacenter1 to Internet” | Remove-ADPermission -User “NT AUTHORITY\ANONYMOUS LOGON” -ExtendedRights ms-Exch-Send-Headers-Routing
After running that command, I needed to wait for EdgeSync to run (or run it manually) before the change would take effect. After the change has taken effect, outbound messages no longer contain the internal server names and IP addresses in the headers. Only the Edge Transport server name and IP address are shown.
If you need to reverse the change, use Add-AdPermission instead of Remove-AdPermission.
|[PS] C:\>Get-SendConnector “EdgeSync – Datacenter1 to Internet” | Add-ADPermission -User “NT AUTHORITY\ANONYMOUS LOGON” -ExtendedRights ms-Exch-Send-Headers-Routing