xref: /openbsd-src/usr.sbin/mailwrapper/mailwrapper.8 (revision b2ea75c1b17e1a9a339660e7ed45cd24946b230e)
1.\"	$OpenBSD: mailwrapper.8,v 1.4 2000/06/11 21:03:40 millert Exp $
2.\"	$NetBSD: mailwrapper.8,v 1.5 1999/03/22 18:44:01 garbled Exp $
3.\"
4.\" Copyright (c) 1998
5.\" 	Perry E. Metzger.  All rights reserved.
6.\"
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8.\" modification, are permitted provided that the following conditions
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17.\"	This product includes software developed for the NetBSD Project
18.\"	by Perry E. Metzger.
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33.\" The following requests are required for all man pages.
34.Dd December 16, 1998
35.Dt MAILWRAPPER 8
36.Os
37.Sh NAME
38.Nm mailwrapper
39.Nd invoke appropriate MTA software based on configuration file
40.Sh SYNOPSIS
41Special.
42See below.
43.Sh DESCRIPTION
44At one time, the only Mail Transfer Agent (MTA) software easily available
45was
46.Xr sendmail 8 .
47As a result of this, most Mail User Agents (MUAs) such as
48.Xr mail 1
49had the path and calling conventions expected by
50.Xr sendmail 8
51compiled in.
52.Pp
53Times have changed, however.
54On a modern system, the administrator may wish to use one of several
55available MTAs.
56.Pp
57It would be difficult to modify all MUA software typically available
58on a system, so most of the authors of alternative MTAs have written
59their front end message submission programs so that they use the same
60calling conventions as
61.Xr sendmail 8
62and may be put into place instead of
63.Xr sendmail 8
64in
65.Pa /usr/sbin/sendmail .
66.Pp
67.Xr sendmail 8
68also typically has aliases named
69.Xr mailq 1
70and
71.Xr newaliases 8
72linked to it.
73The program knows to behave differently when its
74.Va argv[0]
75is
76.Dq mailq
77or
78.Dq newaliases
79and behaves appropriately.
80Typically, replacement MTAs provide similar
81functionality, either through a program that also switches behavior
82based on calling name, or through a set of programs that provide
83similar functionality.
84.Pp
85Although having replacement programs that plug replace
86.Xr sendmail 8
87helps in installing alternative MTAs, it essentially makes the
88configuration of the system depend on hard installing new programs in
89.Pa /usr .
90This leads to configuration problems for many administrators, since
91they may wish to install a new MTA without altering the system
92provided
93.Pa /usr .
94(This may be, for example, to avoid having upgrade problems when a new
95version of the system is installed over the old.)
96They may also have a shared
97.Pa /usr
98among several
99machines, and may wish to avoid placing implicit configuration
100information in a read-only
101.Pa /usr .
102.Pp
103The
104.Nm
105program is designed to replace
106.Pa /usr/sbin/sendmail
107and to invoke an appropriate MTA instead of
108.Xr sendmail 8
109based on configuration information placed in
110.Pa /etc/mailer.conf .
111This permits the administrator to configure which MTA is to be invoked on
112the system at run time.
113.Sh FILES
114Configuration for
115.Nm
116is kept in
117.Pa /etc/mailer.conf .
118.Pa /usr/sbin/sendmail
119is typically set up as a symlink to
120.Nm
121which is not usually invoked on its own.
122.Sh DIAGNOSTICS
123.Nm
124will return an error value and print a diagnostic if its configuration
125file is missing or malformed, or does not contain a mapping for the
126name under which
127.Nm
128was invoked.
129.Sh SEE ALSO
130.Xr mail 1 ,
131.Xr mailq 1 ,
132.Xr mailer.conf 5 ,
133.Xr newaliases 8 ,
134.Xr sendmail 8
135.Sh AUTHORS
136Perry E. Metzger <perry@piermont.com>
137.Sh BUGS
138The entire reason this program exists is a crock.
139Instead, a command
140for how to submit mail should be standardized, and all the "behave
141differently if invoked with a different name" behavior of things like
142.Xr mailq 1
143should go away.
144