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<!-- ISBN=0672311739 //-->

<!-- TITLE=RED HAT LINUX 2ND EDITION //-->

<!-- AUTHOR=DAVID PITTS ET AL //-->

<!-- PUBLISHER=MACMILLAN //-->

<!-- IMPRINT=SAMS PUBLISHING //-->

<!-- PUBLICATION DATE=1998 //-->

<!-- CHAPTER=07 //-->

<!-- PAGES=0097-0130 //-->

<!-- UNASSIGNED1 //-->

<!-- UNASSIGNED2 //-->









<P><CENTER>

<a href="0103-0105.html">Previous</A> | <a href="../ewtoc.html">Table of Contents</A> | <a href="0109-0112.html">Next</A>

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<A NAME="PAGENUM-106"><P>Page 106</P></A>













<P>and the file /home/alphonse/homeboys.aliases contains

</P>





<!-- CODE SNIP //-->

<PRE>

alphonse

joe

betty

george

</PRE>

<!-- END CODE SNIP //-->











<P>the effect is the same as the alias

</P>





<!-- CODE SNIP //-->

<PRE>

homeboys: alphonse, joe, betty, george

</PRE>

<!-- END CODE SNIP //-->











<P>This directive is handy for mailing lists that change frequently or those managed by users

other than the postmaster. If you find a user is asking for frequent changes to a mail alias, you

might want to put it under his or her control.

</P>









<H4><A NAME="ch07_ 13">





Mail to Programs

</A></H4>









<P>The aliases file also can be used to send the contents of e-mail to a program. For example,

many mailing lists are set up so that you can get information about the list or subscribe to it by

sending a letter to a special address,

list-request. The letter usually contains a single word in its

body, such as help or subscribe, which causes a program to mail an information file to the

sender. Suppose that the gonzo mailing list has such an address called

gonzo-request:

</P>





<!-- CODE SNIP //-->

<PRE>

gonzo-request: |/usr/local/lib/auto-gonzo-reply

</PRE>

<!-- END CODE SNIP //-->











<P>In this form of alias, the pipe symbol (|) tells

sendmail to use the program mailer, which is usually defined as

/bin/sh. (See &quot;The M Operator&#151;Mailer Definitions&quot; later in this

chapter.) sendmail feeds the message to the standard input of

/usr/local/lib/auto-gonzo-reply, and if it exits normally,

sendmail considers the letter to be delivered.

</P>









<H4><A NAME="ch07_ 14">





Mail to Files

</A></H4>









<P>You can also create an alias that causes

sendmail to send mail to files. An example is the

alias nobody, which is common on systems running the Network File System (NFS):

</P>





<!-- CODE SNIP //-->

<PRE>

nobody: /dev/null

</PRE>

<!-- END CODE SNIP //-->











<P>Aliases that specify files cause sendmail to append its message to the named file. Because

the special file /dev/null is the UNIX bit bucket, this alias simply throws mail away.

</P>









<H4><A NAME="ch07_ 15">





Setting Up sendmail

</A></H4>









<P>The easiest way to show you how to set up

sendmail is to use a concrete example.

</P>









<P>First, you must obtain the source and compile

sendmail. Next, you must choose a sendmail.cf file that closely models your site's requirements and tinker with it as necessary. Then you

must test sendmail and its configuration file. Finally, you must install

sendmail, sendmail.cf, and other auxiliary files.

</P>



<A NAME="PAGENUM-107"><P>Page 107</P></A>













<P>The preceding are the basic steps, but depending on where you install

sendmail, you might also have to modify a file in the directory

/etc/init.d so that sendmail will be started

correctly when the system boots. In addition, if your system doesn't already have one, you must

create an aliases file, often named

/usr/lib/aliases or /etc/mail/aliases (the location of the

aliases file is given in sendmail.cf, so you can put it wherever you want). You might also have to

make changes to your system's DNS database, but that information is not covered here

(see Chapter 13).

</P>









<H4><A NAME="ch07_ 16">





Obtaining the Source

</A></H4>









<P>Red Hat Linux ships with sendmail 8.8.5, and an RPM version is available from

the www.redhat.com Web site to bring this up to version 8.8.7. Unfortunately, this isn't the

latest version, and sendmail 8.8.7 has a serious security flaw that was recently published

in comp.security.announce. If you are concerned with security (and you should be!), you will

want to download the latest version of sendmail, 8.8.8.

</P>









<P>sendmail version 8.8.8 is on the Red Hat Linux

Unleashed CD-ROM. This is the most recent version available as this book goes to press, and it is the version documented in the

O'Reilly book sendmail, 2nd Ed. (ISBN 1-56592-222-0). This version of

sendmail is available from the site at

<a href="http://www.sendmail.org">http://www.sendmail.org</A> or via FTP at

ftp://ftp.sendmail.org. Using FTP, take the following steps to download it:

</P>







<!-- CODE //-->

<PRE>

[root@gonzo src]# ftp ftp.sendmail.org

Connected to pub1.pa.vix.com.

220 pub1.pa.vix.com FTP server (Version wu-2.4(1) Fri Dec 29 06:15:49 GMT 1995)

ready.

Name (ftp.sendmail.org:root):anonymous

331 Guest login ok, send your complete e-mail address as password.

Password: mylogin@gonzo.gov &lt;--- this will not be echo'ed back to you.

230 Guest login ok, access restrictions apply.

Remote system type is UNIX.

Using binary mode to transfer files.

ftp&gt; cd ucb/src/sendmail

250-This directory contains sendmail 8.x source distributions.  The latest

250-production version is in sendmail.${VER}.tar.{Z,gz,sig} -- the .Z file

250-is compressed, the .gz file is the same bits gzipped, and the .sig file

250-is a PGP signature for the uncompressed bits in either of the first two

250-files.  Please take ONLY ONE of the .Z or .gz files.

250-

250-The status of various interesting ${VER}s is:

250-8.8.8  Many mostly minor fixes -- see RELEASE_NOTES for details.

250-8.8.7  Fixes a few problems where 8.8.6 was too paranoid.

250-8.8.6  Many mostly minor fixes -- see RELEASE_NOTES for details.

250-8.8.5  Fixes a critical security bug as well as several small problems.

250-8.8.4  Fixes several small bugs, including a potential security problem

250-       on some systems allowing local users to get the group permissions

250-       of other users, as well as a rare denial-of-service attack.  It

250-       also fixes the &quot;HUP to smtpd&quot; root shell vulnerability in 8.8.2

250-       described in CERT Advisory CA-96.24.

250-

</PRE>

<!-- END CODE //-->





<A NAME="PAGENUM-108"><P>Page 108</P></A>





<!-- CODE //-->

<PRE>

250-The following versions are unsupported:

250-8.7.6  A security patch for CERT Advisory CA-96.20.

250-       *** SEE ALSO sendmail.8.7.6.patch.1 ***

250-       This version DOES NOT FIX the &quot;HUP to smtpd&quot; root shell problem.

250-

250-There is NO 8.6.* patch for CA-96.20.  8.6 is not supported, not secure,

250-and should not be run on any network-connected machine.

250-

250 CWD command successful.

ftp&gt; bin

200 Type set to I.

ftp&gt; get sendmail.8.8.8.tar.gz

local: sendmail.8.8.8.tar.gz remote: sendmail.8.8.8.tar.gz

200 PORT command successful.

150 Opening BINARY mode data connection for sendmail.8.8.8.tar.gz (1026343 bytes

).

226 Transfer complete.

1026343 bytes received in 717 secs (1.4 Kbytes/sec)

ftp&gt; bye

221 Goodbye.

[root@gonzo src]#

</PRE>

<!-- END CODE //-->











<P>Note that the exact name of the files to download differs depending on the current

version of V8 sendmail, in this case version 8.8.8. Also, because the files are compressed, you must

give FTP the binary command before transferring them. Note, too, that you should include

your complete e-mail address as the password&#151;for example,

mylogin@gonzo.gov.

</P>









<H4><A NAME="ch07_ 17">





Unpacking the Source and Compiling sendmail

</A></H4>









<P>Now that you've got the source, you need to unpack it. (If you're using the version from

the CD-ROM and the sendmail RPM package files, these steps are not necessary.) Because it's

a compressed tar image, you must first decompress it and then extract the individual files

from the tar archive. For this example, I'll assume that the file is currently in

/usr/local/src.

</P>





<!-- CODE //-->

<PRE>

[root@gonzo src]# tar -xzf sendmail.8.8.8.tar.gz

[root@gonzo src]# ls -l

drwxr-xr-x  13 30005    ver          1024 Nov  4 20:34 sendmail-8.8.8

-rw-r--r--   1 root     root      1026343 Nov  4 20:33 sendmail.8.8.8.tar.gz

</PRE>

<!-- END CODE //-->











<P>Now you're almost ready to compile sendmail, but first read the following files, which

contain the latest news pertinent to the specific release of

sendmail you've downloaded:

</P>





<!-- CODE SNIP //-->

<PRE>

FAQ

RELEASE_NOTES

KNOWNBUGS

READ_ME

</PRE>

<!-- END CODE SNIP //-->











<P>Also take note that the Sendmail Installation and Operation

Guide (SIOG) is in the doc/op subdirectory.

</P>









<P>Now run cd and ls to see what files are in the source directory:

</P>





<!-- CODE //-->

<PRE>

[root@gonzo src]# cd sendmail-8.8.8/src

[root@gonzo src]# ls

Makefile      collect.c     macro.c       parseaddr.c   srvrsmtp.c

Makefiles     conf.c        mailq.0       pathnames.h   stab.c

</PRE>

<!-- END CODE //-->





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