Sun Microsystems Sun Workstation 100U System Manager's Manual page 321

SENDMAIL
o
3.2. Mall to FD. and ProFama
Files and programs are legitimate message recipients. Files provide archival storage
of messages, useful for project administration and history. Programs are useful as reci-
pients in a variety 01 situations, lor example, to maintain a public repository 01 systems
messages (such as the Berkeley mIl' program, or the MARS system (Sattley78)).
Any address passing through the initial parsing algorithm as a local address (i.e, not
appearing to be a valid address lor another mailer) is scanned lor two special cases. II
prefixed by a vertical bar ("
I")
the rest of the address is processed as a shell command. II
the user name begins with a slash mark
("I")
the name is used as a file name, instead of a
login name.
Files that have setuid or setgid bits set but no execute bits set have those bits
honored if sendmail is running as root.
3.3. Allasing, Forwarding, Induslon
Sendmail reroutes mail three ways. Aliasing applies system wide. Forwarding allows
each user to reroute incoming mail destined lor that account. Inclusion directs
,endmlJil
to
read a file for a list of addresses, and is normally used in conjunction with aliasing.
3.3.1. AllulnS
Aliasing maps names to address lists using a system-wide file. This file is indexed
to speed access. Only names that parse as local are allowed as aliases; this guarantees a
unique key (since there are no nicknames lor the local host).
3.3.2. Forwardlns
After aliasing, recipients that are local and valid are checked lor the existence of
a ".rorward" file in their home directory. If it exists, the message is
not
sent to that
user, but rather to the list or users in that file. Often this list will contain only one
address, and the feature will be used lor network mail forwarding.
Forwarding also permits a user to specify a private incoming mailer. For exam-
ple, forwarding to:
"I
lusr Ilocal/newmail myname"
will use a different incoming mailer.
3.3.3. Induslon
Inclusion is specified in RFC 733 (Crocker77aJ syntax:
:Include: path name
An address of this form reads the file specified by
plJthname
and sends to all users listed
in that file.
The intent is
not
to support direct use 01 this feature, but rather to use this as a
subset 01 aliasing. For example, an alias 01 the lorm:
project: :include:/usr Iproject/userlist
is a method 01 letting a project maintain a mailing list without interaction with the sys-
tem administration, even il the alias file is protected.
It is not necessary to rebuild the index on the alias database when a :include: list
is changed.
3.4. Me88ap CoUectlon
Once all recipient addresses are parsed and verified, the message is collected. The
message comes in two parts: a message header and a message body, separated by a blank
Venion 4.1 DRAFT
Lut Mod 8/20/83