Topic Last Modified: 2007-01-24

You can route all outgoing messages for remote domains through a smart host instead of using DNS resolution to route them directly to the domain. This enables you to route messages over a connection that may be more direct or less costly than other routes. The smart host resembles the route domain option for remote domains. The difference is that, after you designate smart host, all outgoing messages are routed to that server. With a route domain, only messages for the remote domain are routed to a specific server.

Make sure that your designated smart host is secure and administered by a trusted authority, especially when forwarding sensitive information.

If you set up a smart host, you can still designate a different route for a remote domain. The route domain setting overrides the smart host setting.

You can identify the smart host by the fully qualified domain name (FQDN) or an IP address. However, if you change the IP address, you must change the IP address on every virtual server. If you use an IP address, enclose it in brackets ([ ]) to increase system performance. The SMTP service checks first for a server name, and then an IP address. The brackets identify the value as an IP address, so that the DNS lookup is bypassed.


To set up a smart host

  1. In Microsoft Management Console, select the SMTP virtual server, and then click Properties on the Action menu.

  2. On the Delivery tab, click Advanced to open the Advanced Delivery dialog box.

  3. In Smart host, type the FQDN or the IP address of the smart host server.

  4. If you want the SMTP service to try to deliver remote messages directly before forwarding them to the smart host server, select the Attempt direct delivery before sending to smart host check box. The default is to send all remote messages to the smart host, not to try direct delivery.