Knowledge Base

FIX: Recipient filtering does not work as expected when you use Microsoft Solution for Hosted Messaging and Collaboration 3.5 together with the SMTP domains event sink (Smtpdomx.dll)

Article ID: 924277

Article Last Modified on 10/10/2007

APPLIES TO

Microsoft Solution for Hosted Messaging and Collaboration 3.5

SYMPTOMS

When you use Microsoft Solution for Hosted Messaging and Collaboration 3.5 together with the Simple Mail Transfer Protocol (SMTP) domains event sink (Smtpdomx.dll) to handle domain management, recipient filtering does not work as expected.

CAUSE

This problem is caused by the way that the SMTP domains event sink validates the domain part of an incoming recipient address and by the way that recipient filtering tries to validate the domain. Because of the different methods of validating the domain, recipient filtering does not work as expected.

RESOLUTION

Hotfix information

To resolve this problem, apply the hotfix that is described in Microsoft Knowledge Base article 931524. For more information, click the following article number to view the article in the Microsoft Knowledge Base:

931524 Hosted Messaging and Collaboration version 3.5 users receive a "550 5.1.1 User unknown" NDR message

Hotfix installation information

To apply this hotfix and to configure this hotfix, follow these steps:

Apply the hotfix that is described in Microsoft Knowledge Base article 921101. For more information, click the following article number to view the article in the Microsoft Knowledge Base:

921101 A recipient filter in Exchange Server 2003 does not work when you use Microsoft Solution for Hosted Messaging and Collaboration version 3.5

Important Do not make the registry changes that are described in Microsoft Knowledge Base article 921101 at this point. Only apply the hotfix.
Unregister the existing Smtpdomx.dll file. To do this, follow these steps:
1. On the SMTP server, click Start, click Run, type control admintools, and then click OK.
2. Double-click Services.
3. Right-click Simple Mail Transfer Protocol (SMTP), and then click Stop.
4. Click Start, click Run, type cmd, and then click OK.
5. Change to the directory where the SMTP event sink is currently installed.
  
  By default, the directory is C:\SMTPEventSink. For example, type cd C:\SMTPEventSink, and then press ENTER.
6. Type the following command, and then press ENTER:
  
  Regsvr32 /u smtpdomx.dll
Create the relay SMTP virtual server. To do this, follow these steps:
1. Assign an additional IP address to the SMTP server.
2. Create a Domain Name System (DNS) record for the original IP address that is assigned to the SMTP server.
3. Update the existing MX record to point to the new DNS record.
4. Update the original DNS record with the new IP address.
5. Make sure that the SMTP server is assigned to listen to the new IP address that is assigned to the SMTP server.
6. Install a new SMTP virtual server that listens to the original IP address, make sure that recipient filtering is disabled, and then make sure that relaying for authenticated users is disabled.
7. Wait for the DNS entries to be updated.
  
  Typically, this process takes four hours. However, this process may be shorter or may be longer. The length of time depends on the cache settings that are specified in the DNS server.
Note You have to follow these steps to let users send e-mail messages by using the SMTP server.

For example, assume that the MX record points to the following DNS name:

smtp.example.com

Additionally, assume that users send e-mail messages by using the following DNS name:

smtp.example.com

You have the following IP addresses assigned to the SMTP server:
- The IP address 192.168.0.1 is the original IP address.
- The IP address 192.168.0.2 is the new IP address.
If you use smtp2.example.com as the new DNS name, the following changes occur:
- Smtp2.example.com is assigned the IP address 192.168.0.1.
- Smtp.example.com is assigned the IP address 192.168.0.2.
- The MX record is updated to use smtp2.example.com.
- SMTP virtual server 1 listens to the IP address 192.168.0.2.
- SMTP virtual server 2 listens to the IP address 192.168.0.1.
Note These changes are necessary because the changes that are required to enable recipient filtering prohibit relaying. An alternative to the previous example is to set up another SMTP server for relaying that does not support incoming e-mail messages. Therefore, the SMTP server does not require recipient filtering.
Install the updated Smtpdomx.dll file from the hotfix that is described in Microsoft Knowledge Base article 931524. To do this, follow these steps:
1. Copy the updated Smtpdomx.dll file to the C:\SMTPEventSink directory or to the existing directory.
2. Click Start, click Run, type cmd, and then click OK.
3. Type the following command, and then press ENTER:
  
  Regsvr32 smtpdomx.dll
4. Start Notepad, and then open the Smtpdomx.reg file that is located in the C:\SMTPEventSink directory.
5. In the Smtpdomx.reg file, change the value of the RefreshInterval property to a hexadecimal value of 00000258, and then make sure that the value of the Filename property is empty.
  
  Note The hexadecimal value of 00000258 equals 600 seconds. You should set the interval to a value that is appropriate for your environment.
6. Make sure that the Domains.dat file is in the same directory as the Smtpdomx.dll file.
7. Save the Smtpdomx.reg file.
8. To update the registry with the new key value, double-click the Smtpdomx.reg file.
Make the registry changes that are described in Microsoft Knowledge Base article 921101, and then enable recipient filtering on the relay SMTP virtual server only.
Enable recipient filtering for the incoming SMTP connection.
Restart the Internet Information Services (IIS) Admin service. To do this, follow these steps:
1. Click Start, click Run, type control admintools, and then click OK.
2. Double-click Services.
3. Right-click IIS Admin, and then click Restart.
Configure the Microsoft Exchange back-end servers to use the relay SMTP virtual server to send outgoing external e-mail messages. To do this, use Exchange System Manager to add a new SMTP connector that has the following properties:
- The address space should be an asterisk (*).
- The cost should be 1.
- The connector scope should be for the whole organization.
- The bridgehead for the connection should be set to the relay SMTP virtual server that you created in step 3.

STATUS

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

MORE INFORMATION

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

824684 Description of the standard terminology that is used to describe Microsoft software updates

Keywords: kbhotfixserver kbqfe kbfix kbbug kbpubtypekc KB924277

Microsoft KB Archive/924277

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