Mail flow stops working after you create a new recipient policy or after you configure a connector in Exchange 2000 and in Exchange 2003

You may experience the following symptoms in your Microsoft Exchange 2000 Server organization or in your Microsoft Exchange Server 2003 organization:

• Mail flow unexpectedly stops in a particular domain.
• If you access your Exchange computer by using the Telnet tool, and you try to send an e-mail message, you receive the following error message:
  421 4.1.0 Dropping connection due to an error on this server.
  You may experience these symptoms after you create a new recipient policy or after you configure a connector in your domain.
  
  Note To establish a Telnet session with the Exchange computer, follow these steps:
  1. Click Start, click Run, type cmd, and then click OK.
  2. In the Command Prompt window, type telnet, and then press ENTER.
  3. Type open your mail server name 25, and then press ENTER.
  4. Type ehlo, and then press ENTER.
  5. Type mail from:user name@your domain name, and then press ENTER.

This issue occurs when the domain part of a metabase domain contains two periods. This is typically known as a "double dot" in the domain part of your domain name. For example, this issue occurs if the metabase has a domain that resembles the following:This issue may also occur when the SMTP address has a period at the end. For example, this issue occurs when the domain resembles the following: You may experience this issue if one or more of the following conditions are true:

• An e-mail address recipient policy has a filter, and the e-mail address recipient policy contains two periods in the domain part of the domain name.
• A connector address space that contains two periods in the domain part of the domain name is imported into the Active Directory directory service.
  
  Under these conditions, the metabase update service that is part of the Microsoft Exchange System Attendant service sends the syntactically incorrect domain name to the metabase. The metabase update service does not remove the second period from the domain part of the domain name. Therefore, errors occur unexpectedly at the Simple Mail Transfer Protocol (SMTP) level, and all mail flow stops working.

To resolve this issue, follow these steps.

Step 1: Verify the domain name in the recipient policy

To correct the SMTP proxy address in the recipient policy in Exchange System Manager, follow these steps:

1. Start Exchange System Manager.
2. Expand Recipients, and then click Recipient Policies.
3. In the right pane, right-click a recipient policy, and then click Properties.
4. Click the E-mail Addresses (Policy) tab.
5. In the Generation Rules list, click the SMTP entry, and then click Edit.
6. Verify that the entry in the Address box contains only one period in the domain part of the address.
   
   For example, verify that the SMTP address appears similar to the following:
   @tailspintoys.com
7. Click OK two times.

After you modify the recipient policy, the metabase update service sends this updated information to the metabase.

If the incorrect domain name does not appear in a recipient policy, the incorrect domain name may have been put in the metabase by some other method, such as by a connector. Therefore, the metabase update service may not update the metabase to correct the domain name.

Step 2: Modify the domain name in the metabase

Warning If you edit the metabase incorrectly, you can cause serious problems that may require that you reinstall any product that uses the metabase. Microsoft cannot guarantee that problems that result if you incorrectly edit the metabase can be solved. Edit the metabase at your own risk.

Note Always back up the metabase before you edit it.

To remove the second period from the domain name, use a metabase editor, such as MetaEdit. MetaEdit is a tool that you can use to view the metabase, to view or to set properties in the metabase, to back up the metabase, and to import and to export the metabase.

1. Start MetaEdit.
2. Expand LM, expand SmtpSvc, expand 1, and then expand Domain.
3. Under Domain, right-click the domain name that contains two periods, and then click Rename.
4. Type the correct domain name, and then press ENTER.
5. Quit MetaEdit.

For more information, click the following article number to view the article in the Microsoft Knowledge Base: