Exchange 2003 & 2007 - Locking Down the Server

Microsoft Exchange 2003 and 2007 can be locked down to only accept email from the MailRoute servers by following these steps:

  1. Open Exchange System Manager
  2. Go to Servers -> [MailServer Name] -> SMTP
  3. Right click and go to Properties for Default SMTP Virtual Server
  4. Click the Access tab
  5. Click Connections
  6. Choose Only the List Below
  7. Click Add -> Group of Computers and enter our network block:
    • Subnet Address:
    • Subnet Mask:

Microsoft has an Administration Guide for Microsoft Exchange Server 2003 available at



NOTE: If you stop receiving email and your configuration / firewall has not changed, please check the permissions then select allow anonymous users.

Link to Microsoft Exchange Article About Permissions and Anonymous Users;


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