xref: /titanic_50/usr/src/man/man1m/mailwrapper.1m (revision c536b1f93b31eba539c635a91be8ee2ab0fcb15a)
1.\"	$OpenBSD: mailwrapper.8,v 1.10 2009/02/07 16:58:23 martynas Exp $
2.\"	$NetBSD: mailwrapper.8,v 1.11 2002/02/08 01:38:50 ross Exp $
3.\" $FreeBSD: releng/9.1/usr.sbin/mailwrapper/mailwrapper.8 205938 2010-03-30 21:54:25Z delphij $
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5.\" Copyright (c) 1998
6.\" 	Perry E. Metzger.  All rights reserved.
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34.Dd August 7, 2006
35.Dt MAILWRAPPER 1M
36.Os
37.Sh NAME
38.Nm \fB/usr/lib/mailwrapper\fR
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 1M .
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 1M
51compiled in.
52.Pp
53Times have changed, however.
54On a modern
55.Ux
56system, the administrator may wish to use one of several
57available MTAs.
58.Pp
59It would be difficult to modify all MUA software typically available
60on a system, so most of the authors of alternative MTAs have written
61their front end message submission programs so that they use the same
62calling conventions as
63.Xr sendmail 1M
64and may be put into place instead of
65.Xr sendmail 1M
66in
67.Pa /usr/lib/sendmail .
68.Pp
69.Xr sendmail 1M
70also typically has aliases named
71.Xr mailq 1
72and
73.Xr newaliases 1M
74linked to it.
75The program knows to behave differently when its
76.Va argv[0]
77is
78.Dq mailq
79or
80.Dq newaliases
81and behaves appropriately.
82Typically, replacement MTAs provide similar
83functionality, either through a program that also switches behavior
84based on calling name, or through a set of programs that provide
85similar functionality.
86.Pp
87Although having drop-in replacements for
88.Xr sendmail 1M
89helps in installing alternative MTAs, it essentially makes the
90configuration of the system depend on hand installing new programs in
91.Pa /usr .
92This leads to configuration problems for many administrators, since
93they may wish to install a new MTA without altering the system
94provided
95.Pa /usr .
96(This may be, for example, to avoid having upgrade problems when a new
97version of the system is installed over the old.)
98They may also have a shared
99.Pa /usr
100among several
101machines, and may wish to avoid placing implicit configuration
102information in a read-only
103.Pa /usr .
104.Pp
105The
106.Nm
107utility is designed to replace
108.Pa /usr/lib/sendmail
109and to invoke an appropriate MTA instead of
110.Xr sendmail 1M
111based on configuration information placed in
112.Pa /etc/mailer.conf .
113This permits the administrator to configure which MTA is to be invoked on
114the system at run time.
115.Pp
116Other configuration files may need to be altered when replacing
117.Xr sendmail 1M .
118.Sh EXIT STATUS
119.Ex -std
120.Sh DIAGNOSTICS
121The
122.Nm
123will print a diagnostic if its configuration file is missing or malformed,
124or does not contain a mapping for the name under which it was invoked.
125.Sh SEE ALSO
126.Xr mail 1 ,
127.Xr mailq 1 ,
128.Xr newaliases 1M ,
129.Xr mailer.conf 4 ,
130.Xr sendmail 1M
131