Users can still send and receive e-mail messages after you disable Internet e-mail by using the Configure E-mail and Internet Connection Wizard (829038)

WORKAROUND

Warning If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.

To work around this problem, configure Exchange Server to permit internal e-mail messages but to block e-mail to and from external domains. To do this, follow these steps.

Note These steps apply to Windows Small Business Server 2003 that is running SMTP mail service. These steps do not apply to computers that are running Windows Small Business Server 2003 and that send and receive e-mail messages by using the POP3 connector, ETurn, or a Smarthost.

1. Run the Configure E-mail and Internet Connection Wizard to re-enable Internet e-mail for your domain.
2. Start Exchange System Manager. To do this, click Start, point to All Programs point to Microsoft Exchange, and then click System Manager.
3. Expand Connectors, right-click SmallBusiness SMTP connector, and then click Properties.
4. Click the Delivery Restrictions tab, click Rejected, click Apply, and then click OK.
5. Expand Servers, expand your computer that is running Windows Small Business Server 2003, expand Protocols, expand SMTP, right-click Default SMTP Virtual Server, and then click Properties.
6. Click the Access tab, and then click Connection.
7. Click Only the list below, click OK, and then click OK.
8. Exit Exchange System Manager.
9. Click Start, click Run, type regedit in the Open box, and then click OK.
10. Locate, and then click the following registry subkey:

    HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\RESvc\Parameters

11. In the Parameters key, create the following registry entry:

    Entry type: REG_DWORD
    Entry name: CheckConnectorRestrictions
    Entry value: 1
    Entry radix: hexadecimal

12. Exit Registry Editor.
13. Restart the following services:

    Microsoft Exchange Routing Engine
    Simple Mail Transfer Protocol (SMTP)

After you follow these steps, e-mail functionality is changed as follows:

• Internal e-mail functions as you expect.
• External inbound e-mail is not delivered to the computer that is running Windows Small Business Server 2003. If you use Telnet to connect to port 25 on the external interface, you receive a blinking cursor. The SMTP server does not respond.
• When users try to send messages to external domains, they receive the following error message:
  You do not have permission to send to this recipient.