XIMS: SMTP Service Routes All SMTP Mail to Smart Host

A server running the Microsoft SMTP service, available in the Microsoft products listed at the beginning of this article, may not correctly route e-mail to the host that is specified by a remote domain definition. Instead, the e-mail is always routed by using the smart host that is defined in the SMTP Site properties.

You can create remote domains in the Internet Service Manager by clicking to select Default SMTP Site/Domains, clicking New on the Actions menu, and then clicking Domain. You can configure each new domain to be remote, in which case the Route Domain box specifies the SMTP host that e-mail destined for this remote domain is forwarded to. An e-mail message sent to a single recipient in this domain is forwarded by using this host. However, if another recipient is included in the same e-mail message, and that recipient is not part of the remote domain, the e-mail message is delivered by using the smart host only. A connection to the route domain host is not made.

A supported fix is now available from Microsoft, but it is only intended to correct the problem that is described in this article. Apply it only to computers that are experiencing this specific problem.

To resolve this problem, contact Microsoft Product Support Services to obtain the fix. For a complete list of Microsoft Product Support Services phone numbers and information about support costs, visit the following Microsoft Web site:NOTE: In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question.

The English version of this fix should have the following file attributes or later:

Component: Mail Server


To enable this capability, you need to modify the Metabase. You can make this modification by using the Smtpmd.exe utility that is supplied with the fix above. The following are complete instructions about how to apply the fix and make this change:

1. Copy the Smtpmd.exe utility to a folder on the system (for example, the C:\Temp folder).
2. Stop all of the services that are based on the Internet Information Service (IIS); to do this, type the following at a command prompt, and then press the ENTER key:
   net stop iisadmin /y
3. Replace the Smtpsvc.dll file on your server. This file is normally located in the C:\Winnt\System32\Inetsvc folder.
4. Type the following from the folder that you copied the Smtpmd.exe utility to:
   smtpmd set smtpsvc/1/routingdomainoverridesmarthost 1
5. Restart all of the required IIS-based services.

You can restore the original behavior; to do this, stop the IIS-based services and run the SMTPMD utility as follows: Then restart all of the required IIS services.

Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article.