HP-UX Mailing Services Administrator's Guide (B2355-91064)

An efficient queue file-naming system is also being provided in this release. The
algorithm used to name files ensures that the names will be unique for 60 years. The
queued items can be moved between queues with ease.
Default Client/Server Operation
This section describes the operation of Sendmail servers and clients. Figure 1-2 shows
a Sendmail server called mailserv and a Sendmail client called mailclient in the
company.com domain. On mailclient, the SENDMAIL_SERVER_NAME in the
/etc/rc.config.d/mailservs file is set to mailserv.company.com. user1 is
a user on mailclient.
Figure 1-2 Sendmail Client-Server Operation
company.com Domain
Local mail to and from
mailclient users
Incoming remote mail to
[e-mail]
Outgoing remote mail to
[e-mail]
mailclient
user1
mailserv
Internet
Incoming remote mail
for user1@mailclient
Outgoing mail from user1 can be local mail that is intended for any user on
mailclient. Local mail is forwarded to mailserv; you specify this by setting the
DH macro entry in the /etc/mail/sendmail.cf file on mailclient. (The Sendmail
installation script sets the DH macro value to the host specified by
SENDMAIL_SERVER_NAME.) Outgoing mail that is not local is sent by mailclient to
the remote host using MX records. Because the DM macro entry in the
/etc/mail/sendmail.cf file on mailclient is set to mailserv.company.com,
mail from user1 appears to be from [e-mail].
Because mail sent to remote hosts from user1 is sent from
[e-mail], replies to user1’s messages are returned to
mailserv. On mailserv, when Sendmail receives mail for user1, it looks up user1
in the aliases database and redirects mail for user1 to user1@mailclient.
You can modify Sendmail server and client operations. Most modifications involve
changing or re-creating the /etc/mail/sendmail.cf file on the server or client
systems. For example, you can define the DM macro on a mail server system. You can
also modify the /etc/mail/sendmail.cf file so that the clients relay all outbound
mail to the server; this is described in “Modifying the Default Sendmail Configuration
File” (page 43).
The Sendmail Utility 33