1.\" $NetBSD: mailwrapper.8,v 1.6 1999/03/25 16:40:17 is Exp $ 2.\" $FreeBSD$ 3.\" 4.\" Copyright (c) 1998 5.\" Perry E. Metzger. All rights reserved. 6.\" 7.\" Redistribution and use in source and binary forms, with or without 8.\" modification, are permitted provided that the following conditions 9.\" are met: 10.\" 1. Redistributions of source code must retain the above copyright 11.\" notice, this list of conditions and the following disclaimer. 12.\" 2. Redistributions in binary form must reproduce the above copyright 13.\" notice, this list of conditions and the following disclaimer in the 14.\" documentation and/or other materials provided with the distribution. 15.\" 3. All advertising materials mentioning features or use of this software 16.\" must display the following acknowledgment: 17.\" This product includes software developed for the NetBSD Project 18.\" by Perry E. Metzger. 19.\" 4. The name of the author may not be used to endorse or promote products 20.\" derived from this software without specific prior written permission. 21.\" 22.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 23.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 24.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 25.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 26.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 27.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 28.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 29.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 30.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 31.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 32.\" 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 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 8 64and may be put into place instead of 65.Xr sendmail 8 66in 67.Pa /usr/sbin/sendmail . 68.Pp 69.Xr sendmail 8 70also typically has aliases named 71.Xr mailq 1 72and 73.Xr newaliases 1 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 replacement programs that plug replace 88.Xr sendmail 8 89helps in installing alternative MTAs, it essentially makes the 90configuration of the system depend on hard 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 107program is designed to replace 108.Pa /usr/sbin/sendmail 109and to invoke an appropriate MTA instead of 110.Xr sendmail 8 111based on configuration information placed in 112.Pa /etc/mail/mailer.conf . 113This permits the administrator to configure which MTA is to be invoked on 114the system at run time. 115.Sh FILES 116Configuration for 117.Nm 118is kept in 119.Pa /etc/mail/mailer.conf . 120.Pa /usr/sbin/sendmail 121is typically set up as a symbolic link to 122.Nm 123which is not usually invoked on its own. 124.Sh DIAGNOSTICS 125.Nm 126will return an error value and print a diagnostic if its configuration 127file is missing or malformed, or does not contain a mapping for the 128name under which 129.Nm 130was invoked. 131.Sh SEE ALSO 132.Xr mail 1 , 133.Xr mailq 1 , 134.Xr newaliases 1 , 135.Xr mailer.conf 5 , 136.Xr sendmail 8 137.Sh HISTORY 138.Nm 139first appeared in 140.Nx 1.4 141and then 142.Fx 4.0 . 143.Sh AUTHORS 144Perry E. Metzger <perry@piermont.com> 145.Sh BUGS 146The entire reason this program exists is a crock. 147Instead, a command 148for how to submit mail should be standardized, and all the "behave 149differently if invoked with a different name" behavior of things like 150.Xr mailq 1 151should go away. 152