| - | Exchange Management Console - Server Configuration - Hub Transport - New Receive Connector |
| - | Give it a name i.e. "Open Relay" and leave "Custom" selected - Next |
| - | Bind it to "All available IP Addresses on Server" through port 25 (assuming this is what you want) |
| - | Enter your FQDN this server should announce itself as - Next |
| - | Remove the default specified remote IP address range and enter in the specific or range of IPs you intend to allow to relay through this host - Next |
| - | Complete the creation of the new receive connector and then edit the properties of the new connector |
| - | Goto the "Authentication" tab and uncheck everything except "Transport Layer Security (TLS)" |
| - | Next goto the "Permissions Groups" tab and uncheck everything except "Anonymous users" - click "Apply" and then "Ok" |
| - | Now we need to edit the connector through the following shell command to enable it for open relay: |
| | o | Get-ReceiveConnector "Open Relay" | Add-ADPermission -User "NT AUTHORITY\ANONYMOUS LOGON" -ExtendedRights "ms-Exch-SMTP-Accept-Any-Recipient" |
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