In Chapter 10, we saw that local deliveries all look up the mailbox in qmail's users database to determine both where to deliver a message, and what user and group ID and home directory to use when making the delivery. Although the most common setup of users is to deliver to the users in /etc/passwd, the users database is considerably more flexible than a mere mirror of the password file. The users database maps each local address to a set of user data including:
The qmail-lspawn program changes to the user and group ID and home directory before starting a delivery, then uses the separator character and extension to locate a .qmail file to control the delivery, as covered in Chapter 10. |