1 .\" $OpenBSD: mailwrapper.8,v 1.12 2014/03/27 22:34:42 jmc Exp $
2 .\" $NetBSD: mailwrapper.8,v 1.16 2014/09/19 16:05:55 wiz Exp $
6 .\" Perry E. Metzger. All rights reserved.
8 .\" Redistribution and use in source and binary forms, with or without
9 .\" modification, are permitted provided that the following conditions
11 .\" 1. Redistributions of source code must retain the above copyright
12 .\" notice, this list of conditions and the following disclaimer.
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17 .\" must display the following acknowledgment:
18 .\" This product includes software developed for the NetBSD Project
19 .\" by Perry E. Metzger.
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39 .Nd invoke appropriate
41 software based on configuration file
46 Once upon time, the only Mail Transfer Agent
48 software easily available was
58 affected most Mail User Agents
62 the path and calling conventions expected by
69 system, the administrator may wish to use one of several available
72 It would be difficult to modify all
74 software typically available on a system,
75 so most of the authors of alternative
77 have written their front end message submission programs
78 that may appear in the place of
79 .Pa /usr/sbin/sendmail ,
80 but still follow the same calling conventions as
86 also typically has aliases named
91 The program knows to behave differently when its
97 and behaves appropriately.
98 Typically, replacement
100 provide similar functionality, either through a program that also
101 switches behavior based on calling name, or through a set of programs
102 that provide similar functionality.
104 Although having replacement programs that plug replace
106 helps in installing alternative
108 it essentially makes the configuration of the system depend
109 on hand installing new programs in
111 This leads to configuration problems for many administrators, since
112 they may wish to install a new
114 without altering the system provided
116 (This may be, for example, to avoid having upgrade problems when a new
117 version of the system is installed over the old.)
118 They may also have a shared
120 among several machines, and may wish to avoid placing
121 implicit configuration information in a read-only
126 program is designed to replace
127 .Pa /usr/sbin/sendmail
128 and to invoke an appropriate
130 based on configuration information placed in
131 .Pa ${LOCALBASE}/etc/mail/mailer.conf
133 .Pa /etc/mail/mailer.conf .
134 This permits the administrator to configure which
137 the system at run time.
139 Other configuration files may need to be altered when replacing
141 For example, if the replacement
147 .Va daily_status_include_submit_mailq
148 should be turned off in
149 .Pa /etc/periodic.conf .
154 .Pa ${LOCALBASE}/etc/mail/mailer.conf
156 .Pa /etc/mail/mailer.conf .
157 .Pa /usr/sbin/sendmail
158 is typically set up as a symbolic link to
160 which is not usually invoked on its own.
166 will print a diagnostic if its configuration file is missing or malformed,
167 or does not contain a mapping for the name under which it was invoked.
174 .Xr periodic.conf 5 ,
179 utility first appeared in
184 .An Perry E. Metzger Aq Mt perry@piermont.com
186 The entire reason this program exists is a crock.
188 for how to submit mail should be standardized, and all the
189 .Dq behave differently if invoked with a different name
190 behavior of things like