Organizing Messages Using SMTP Domains

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Applies To: Windows Server 2003, Windows Server 2003 with SP1

SMTP domains are used for organizing messages for delivery. There are two main types of domains: local and remote.

Organizing Messages Using Local Domains

A local domain is a DNS domain that is serviced by the local SMTP server. Any message with a local domain name that arrives at an SMTP server must be delivered to a local mailbox or drop directory, forwarded to another local address, or returned to the sender with a nondelivery report.

You can specify local domains to be either default or alias. The SMTP service uses the default domain to stamp message headers that lack a domain specification. An alias domain is an alias for the default domain. For example, if Contoso Pharmaceuticals merges with Contoso Corporate, then customers might not know which domain to use. If ContosoPharmaceuticals.com is the default domain, then you can set ContosoCorporate.com as an alias domain, which allows users to send mail to either the ContosoPharmaceuticals.com domain or the ContosoCorporate.com domain so that the mail is still delivered to the correct recipient.

Organizing Messages Using Remote Domains

A remote domain is a domain that is not served by the local SMTP server. When mail is routed to a remote domain and the address is found, the SMTP service sends the mail to another server. Therefore, if you are setting up a smart host as a stand-alone server in front of your Exchange server, then you need to create a remote domain using the domain of your Exchange server.