Supporting Messaging Clients

Set a Fully Qualified Domain Name

Setting a fully qualified domain name (FQDN) is important if your SMTP virtual server is on the Internet. An e-mail domain must be able to be resolved through Domain Name System (DNS). When sending e-mail directly to the Internet, there are two DNS records that are used to resolve an e-mail domain. One of the records, a mail exchange (MX) record, is set up to associate an e-mail domain with the FQDN of one or more SMTP virtual servers that serve that domain.

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 clients use the A record) and another server to handle (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:

  1. Start System Manager
    On the Start menu, point to Programs, point to Microsoft Exchange, and then click System Manager.
  2. Navigate to the SMTP virtual server.
    1. Servers
    2. Server
    3. Protocols
    4. SMTP
    5. SMTP virtual servers
    6. SMTP virtual server
  3. Right-click the SMTP virtual server, and then click Properties.
  4. On the Delivery tab, click Advanced.
  5. In Advanced Delivery, in Fully-qualified domain name, type the FQDN.