Topic Last Modified: 2007-05-16

A remote domain is a domain outside to your organization to which you send e-mail. You can set unique delivery requirements for a specific remote domain by adding a domain and configuring it accordingly. For example, you can set a predetermined delivery route, require authentication, and require that Transport Layer Security (TLS) encryption be used on all connections to the domain. If the remote domain is not configured specifically, Windows Server 2008 SMTP Server will not perform any of these special operations when delivering to this domain. However, it will complete an ordinary DNS lookup.

You can include an asterisk (*) in a remote domain name if it is the first character listed and is followed by a period (.). Using the wildcard indicates that all inclusive domains for the domain that you are creating use the same settings.

For remote domains, you can set the following options on the General tab.

Allow incoming mail to be relayed to this domain

By default, SMTP Server blocks computers from relaying unwanted mail to the remote domain. Select the Allow incoming mail to be relayed to this domain check box to override the relay restriction setting on the Access tab.

Send HELO instead of EHLO

ESMTP defines a method for extending SMTP that enables an SMTP server to inform an SMTP client of the extensions it supports. An SMTP client supporting ESMTP starts an SMTP session by issuing the EHLO command instead of the HELO command. A successful response issues a list of SMTP extensions the server supports. If the server does not support ESMTP, an error is generated. Select the Send HELO instead of EHLO check box to communicate only with HELO when you send to the remote domain.

Outbound security

The authentication and TLS encryption options set on the Delivery tab can be overridden for a specific remote domain. This enables you to set the SMTP virtual server authentication level for most transmissions, while enabling exceptions for individual addresses handled by a particular remote domain. Select Outbound Security to set the authentication level for this remote domain.

Route domain

You can specify one of the following options to control how messages are routed to the remote domain:

• Use DNS to route to this domain Select this option to use DNS name resolution to locate SMTP servers in the remote domain.
  
  
• Forward all mail to smart host Select this option to specify that messages sent to the remote domain are forwarded to a smart host. The smart host setting for a remote domain overrides the virtual server smart host setting on the Delivery tab. Type the fully qualified domain name or IP address of the server through which you want to route messages for this remote domain.