In this configuration, each mail client mounts its mail from one mail server that provides mail spooling for client mailboxes. This server can also be the mail host. This configuration assists the backup of the mailboxes for each client.
To set up this kind of mail configuration, you need:
The default /etc/mail/sendmail.cf file on each mail client system (no editing required)
A server designated as the mail host (add mailhost.domainname to the /etc/hosts file on the mail host; then if you are not running NIS or NIS+, add the mail host IP address line to the /etc/hosts file of all mail clients)
Matching /etc/mail/aliases files on any system that has a local mailbox (unless you are running NIS or NIS+)
Entries in each mail client's /etc/vfstab file or /etc/auto_direct (if autofs is used) to mount the /var/mail directory
Enough space in /var/mail on the mail server to hold the client mailboxes