Exchange 2010 allow internal anonymous relay

Reference:
How to Configure a Relay Connector for Exchange Server 2010
How to anonymously Relay in Exchange Server 2007/ 2010

Exchange Management Console / Server configuration / Hub Transport
=> New Receive Connector (Ex: myRelay)
Local Network Setting: 用預設值
Remote Network Setting: 將預設值刪除，新增內部特定 IP address
Permission Group: Anonymous Users
Authentication: 全部取消

開啟 Exchange Management Shell
Get-ReceiveConnector “myRelay” | Add-ADPermission -User “NT AUTHORITY\ANONYMOUS LOGON” -ExtendedRights “Ms-Exch-SMTP-Accept-Any-Recipient”