How to Disable Open Relay

Protect your email server

Open relay allows all users to send email through an SMTP server. Some of the accessing users will take advantage of this option to deliver spam through your email server, which will cause recipients to mark your server as a source of spam and deny delivery of all messages from it. Then the authentic SMTP mail users who send messages through the server will be unsuccessful at reaching many of their intended recipients. Configure your SMTP server to prevent unauthorized access by shutting off the open relay.

Instructions

1. Click "Start" and roll the mouse pointer over "All programs." Roll the cursor over "Microsoft Exchange" and click the "System Manager" selection.

2. Click on the "Servers" option in the console tree and click on the listed email server you wish to protect. Click on "Protocols" and then "SMTP."

3. Right-click "Default SMTP virtual server" and then click on the "Properties" selection. Click the tab marked "Access." Click the "Authentication" option listed under Access Control to open the authentication dialog box.

4. Click on the box next to Anonymous access to remove the check mark inside. That disables open access to the SMTP server.

References

• Technet Microsoft: How to configure access controls and authentication methods
• Technet Microsoft: Securing your exchange server