A trusted user is one who has three privileges that most users don't have:
When mail is delivered via a program of the user's choosing (such as
(1)), most users need to have a
valid shell in the
password file. Without a valid shell, such program delivery
is prohibited. Invalid shells often exist for pseudo-users such as
and for all users on restricted servers. A trusted
user is exempted from this test.
to take its idea
of the sender from the command line rather than from the
envelope or header. Because the
command line switch
can be used to forge mail,
a warning into the message header. A trusted user is one who is exempted from having such warnings included.
set sender to
In one of its myriad roles,
can speak SMTP to
another program on the same machine. That other program merely has
command-line switch and
talk on its standard output.
(1) program is one such program that can do this.
is run in this way and if the sender's address
doesn't match the executing user's address, then a forged message
may be in the works. When
detects such a possible
forgery, it inserts a warning into the message header:
owned process doing -bs
A trusted user is one who is exempted from having such warnings included.
Trusted users are declared in the configuration file in two ways:
user1 user2 ....
user1 user2 ....
The first line is the old form of declaration, and the second
is the new form (beginning with V8.7
form. The two are equivalent, but the second is recommended.
In the latter form, names of users are added to the class
Trusted users are declared in the
Ct root daemon
because some root-run programs need to send
mail under the identity of other users. We list
for the same reasons and because most long-running background
processes are owned by the user
If your local machine is set up to receive UUCP mail, you
need to add
to this list.
Once you add trusted users to the
you are almost ready to use that file as the official configuration file.