HP-UX Mailing Services Administrator's Guide

Mailing Services Overview
The Sendmail Utility
Chapter 130
If an address resolves to the local mailer, Sendmail looks up the address
in its alias database and expands it appropriately if it is found. The
aliasing facility or a user’s .forward file can be used to route mail to
programs and to files. (Sendmail does not mail directly to programs or
files.) Mail to programs is normally piped to the prog mailer
(/usr/bin/sh -c), which executes the command specified in the alias or
.forward file definition. (You can restrict the programs that can be run
through the aliases or .forward files. See “Security” on page 74 for
more information.) Mail to a file is directly appended to the file by
Sendmail if certain conditions of ownership and permission are met.
After expanding all the aliases, Sendmail routes mail that is addressed
to a local user to the local mailer (/usr/bin/rmail), which deposits the
message in the user’s mailbox.
Default Routing Configuration
The installed configuration file, if unmodified, routes mail depending on
the syntax of the recipient addresses as described in the following
sections.
Local Addresses: The following forms are recognized as local
addresses and are delivered locally:
user
user@localhost
[e-mail]
user@alias
[e-mail]
user@[local_host’s_internet_address]
localhost!user
localhost!localhost!user
[e-mail]
UUCP Addresses: Addresses of the following forms are recognized as
UUCP addresses, where
host is not the local host name:
host!user
host!host!user
[e-mail]