Topic Last Modified: 2005-11-18

The Microsoft® Exchange Server Analyzer Tool queries the Active Directory® directory service to determine whether the configured value for the msExchSmtpSmartHostType attribute has been changed from the default value of 0. By default, the msExchSmtpSmartHostType attribute is set to 0. If the Exchange Server Analyzer finds that this attribute does not have a value of 0, a non-default configuration message is displayed.

The msExchSmtpSmartHostType attribute indicates whether an SMTP virtual server is configured to use a smart host for delivering messages. You can route all outgoing messages for remote domains through a smart host, instead of sending those messages directly to the recipient domains. When Exchange is configured to use a smart host, the value for the msExchSmtpSmartHostType attribute is changed as detailed in the following table.

Smart host setting msExchSmtpSmartHostType attribute value

No smart host


Smart host


Smart host with direct delivery attempted first


On Exchange Server 2003 computers, this value will be either 0 or 2. On Exchange 2000 Server computers, the value can be 0, 1, or 2. A value of 1 is set when the Attempt direct delivery before sending to smart host check box is checked. This check box is only on Exchange 2000 Server computers. Exchange Server 2003 does not include this check box.

Unless you have a specific reason to do this, it is recommended that you leave the msExchSmtpSmartHostType attribute at its default setting of 0.

If your environment requires a smart host, and you have (or are planning to have) more than one Exchange Server computer in your environment, it is recommended that you use an SMTP Connector for any smart host entries. This way all your internal mail is routed by Exchange Server and only your external mail will be routed through the smart host.

To view and configure smart host settings

  1. Open Exchange System Manager.

  2. Expand Servers, expand an Exchange server, expand Protocols, and then expand SMTP.

  3. Right-click an SMTP virtual server (for example, Default SMTP Virtual Server) and select Properties.

  4. Select the Delivery tab, and then click Advanced.

  5. Enter the smart host you want to use. You can identify the smart host by the fully qualified domain name or by an IP address. If you use an IP address, you must enclose it in brackets ([ ]). Exchange checks first for a server name, and then for an IP address. The brackets identify the value as an IP address; therefore, the DNS lookup is bypassed.

  6. If this is an Exchange 2000 Server computer, optionally select the Attempt direct delivery before sending to smart host check box.

  7. Click OK to save the changes, and then click OK to close the Properties dialog box of the SMTP virtual server.

For more information about SMTP virtual server settings, see the following Microsoft Knowledge Base articles: