 | Preparing to Set Up Mail Services |
You can set up a mail service relatively easily if your site does not provide connections to electronic mail services outside of your company or if your company is in a single domain. Setting up complicated sites with multiple domains is beyond the scope of this book. Chapter 2, “Customizing sendmail Configuration Files,” contains information about how to create the more complicated configuration files required for sites with multiple domains.
Mail requires two types of configurations for local mail and a third for communication with networks outside of your domain. These configurations can be combined on the same system or provided by separate systems. Table 19 describes each of these configurations.
| Configuration | Description |
|---|---|
| Mail hub | You need at least one mail hub. The mail hub stores mailboxes in the /var/mail directory. |
| Mail client | Mail clients are users who have mailboxes either locally or on a mail server. |
| Gateway | A gateway is a connection between different communications networks. A relay host manages communication with networks outside of your domain. A relay host can also act as a gateway. You must add rules to the *.mc file used to generate the sendmail.cf file to set up a gateway. See Chapter 2, “Customizing sendmail Configuration Files,” for information about creating a *.mc file. |
Before you begin to set up your mail service, choose the systems that will act as mail hubs and gateways. You should also make a list of all of the mail clients you will be providing service for and indicate the location of their mailboxes. This list will help you when you are ready to create mail aliases for your users. See Chapter 1, “Understanding Mail Services,” for more information about the function each of these systems provides. For your convenience, guidelines about which systems are good candidates for mail hubs and gateways are described in the following sections.