Exchange 2007's new Edge Transport server functionality aims to provide your organization with the highest level of security possible while still maintaining a usable infrastructure. As such, the Edge Transport server is not part of your Active Directory domain. In fact, the Edge Transport server is best placed in your firewall's DMZ where it still needs to be able to communicate with your Hub Transport server. In order to achieve some of Exchange 2007’s more advanced spam filtering features, such as making sure users exist in your environment before allowing mail through the Edge Transport server, the Edge Transport server needs to be able to communicate with your Active Directory infrastructure. This is accomplished via EdgeSync.

In order for EdgeSync to work, your Edge Transport server must have a primary DNS suffix assigned. To do so:

  1. From the Edge Transport server’s desktop, right-click My Computer.
  2. From the shortcut menu, choose Properties to open the System Properties window.
  3. Choose the Computer Name tab.
  4. Click the Change button. This opens the Computer Name Changes window.
  5. Click the more More button to open the DNS Suffix and NetBIOS Computer Name window.
  6. Enter the DNS suffix for your domain.
  7. Click OK until you’re asked if you want to restart the computer.

Further, make sure that an entry for the Edge Transport server exists in your organization’s DNS and that the Edge Transport server uses your organization’s DNS to resolve addresses. Finally, make sure that the communication pathway between the Edge and Hub servers is clear and they can communicate with one another.