Enter the complete e-mail domain name (official host name) for your IMail Server. For example, mail.domain.com.
IMail Server installation wizard attempts to automatically enter the fully qualified domain name of the machine for this field. Confirm (or enter) the official host name of the system on which you are installing IMail Server. This will be the "primary host."
The mail server host name and domain must be registered in the DNS (Domain Name System) in order for remote hosts to be able to communicate with your e-mail server. Your DNS must contain the proper entries for the host name you see here.
If you have any doubts about what to enter for the e-mail domain name, you can exit the installation program and check the DNS information for the system on which you intend to install IMail Server (the primary host).
The DNS server for the local network must appear as the first listed item on the Domain tab menu list box. See Managing Domains for more information.
If you do not want to use the official host name of your server as the name of the primary mail host, you can create an alias for the primary mail host. See Setting Up an Alias for a Host.