Set a Fully Qualified Domain Name
Note If your virtual server is not in the Internet, MX records are not necessary. Within an Exchange organization, connectors have multiple source and destination bridgeheads, which provide the same function as multiple MX records.
Each SMTP server referenced in the MX record must have an address (A) record. The A record maps a given FQDN to its IP address. It's possible to just have an A record set up for an e-mail domain, which is common within an organization's intranet. And in some cases the A record is used for other puposes, such as HTTP, while the MX record is generally used only for SMTP. For example, the MX record allows one server to handle http://microsoft.com (HTTP clients use the A record) and another server to handle firstname.lastname@example.org (SMTP clients use the MX record).
In Exchange there are two options for specifying an FQDN. You can use the name specified on the Network Identification tab of the System properties in Control Panel, or you can specify a unique FQDN for the SMTP virtual server you are configuring.
At startup, the name designated on the Network Identification tab is automatically used for the FQDN. If you change the name (either manually or by joining a Windows 2000 domain), the new name is automatically used for the FQDN the next time the computer is rebooted. No action is required to update the FQDN for the virtual server.
You can also override the automatic use of the computer and domain names on the Network Identification tab and set your own FQDN.
To set an FQDN: