[ netinfo/sendmail-cf-doc.txt ]

From:  Erik Fair

There are two generic sendmail configuration files that I've created:

	internet-generic.cf	- for Internet-only hosts
	generic.cf		- for hosts using both Internet and UUCP

NOTE:   The NIC's filenames are:

        netinfo/sendmail-internet-generic.txt
        netinfo/sendmail-generic.txt

The basic assumptions are:

	If you're an internet host, you're registered (i.e. in
	hosts.txt from the NIC. If you're not, you need to be "hidden"
	behind the name of a host that is registered, in the form:
	user%un
	do that).

	If you're an internet host, you're not using the domain name
	server (if you are, why are you bothering with these config
	files?).

	The gethostname(2) system call returns your unqualified
	official hostname (e.g. "ucbvax", instead of "ucbvax.berkeley.edu").
	This is set by hostname(1), usually in /etc/rc.local at boot
	time, but this can be overridden for the purposes of Email by a
	config file definition.

	If you use UUCP, the gethostname(2) system call returns your
	UUCP name (i.e.  your UUCP name is the last component of your
	fully qualified hostname). This also can be overridden.

OK, the nitty-gritty. The NIC is about to, or already has, issued a
HOSTS.TXT that no longer has any of the non-domainist aliases (e.g.
ucbvax.berkeley.edu doesn't have "berkeley" or "ucbvax" its aliases any
more). As such, you must be prepared to use fully qualified domain
names in all your correspondence. Unfortunately, the sendmail
configuration file distributed with 4.2 BSD (but NOT 4.3 BSD) is
incapable of handling this right. Thus the distribution of my config
files.

To use these, you have to pick one of the generic files, add your
local information to it (all your hostnames & aliases, UUCP sites you
speak to, etc), and install it as /usr/lib/sendmail.cf.

So, here is the stuff you need to change to use these sendmail
configuration files:

		internet-generic.cf

There are two configuration items here: macro "w" and class "w".
Case of a macro or class name is significant. A macro is a string.
A class is an array of strings.

Macro "w" is usually defined by whatever comes back from the
gethostname(2) system call. You can look at this by using the
"hostname" program. When you add ".arpa" to what "hostname" prints, you
should get your official host name. For example, for site lll-tis-b.arpa,

% hostname
lll-tis-b

is correct. If, for whatever reason, "hostname" returns something OTHER
than the first component of your official Internet host name, then you
need to add to the configuration file, (for example)

Dwlll-tis-b

This defines macro "w" to be "lll-tis-b" which will have the desired
effect.

Class "w" is a list of all the names that your host is known by.
This should contain your hostname, and all aliases for your host.
Using the same example as above:

Cwlll-tis-b lll-tis-gw tis-b tis-styx styx

If you need more than one line, use as many lines as you need,
beginning each line in "Cw"

If by some misfortune you run System V UNIX instead of 4BSD, but you
still have sendmail, it is still possible for you to use these
configuration files, but you will have to find the local mailer
definition (this is what sendmail will call to actually stuff a letter
in a local mailbox) which is a line which matches the "^Mlocal"
regular expression, and read the comment surrounding it.

		generic.cf

This configuration file needs the same information as internet-generic.cf,
but also some stuff about UUCP: macro "U" and class "U". Note that it
is also important for your UUCP name to be in class "w" along with your
internet names.

Macro "U" should be defined to be your UUCP name. If your UUCP name is
not the same as what gets returned from gethostname(2) (i.e. it's not
the first component of your official internet host name), then you
have to change the definition of macro "U" in the config file from

DU$w

to

DUyour-uucp-name-here

In the case of "lll-tis-b.arpa", whose UUCP name is "styx", this would
read:

DUstyx

Class "U" is the list of all the UUCP sites that you speak to. This
will have to be updated each time you change the L.sys file in order
for UUCP mail to get through. Use as many lines as you need, beginning
each line with "CU", and separating the names with spaces.

		I N S T A L L A T I O N

Having made the required changes to reflect your local names, you need
to install this. So, how?

First, copy the old sendmail config file to a backup file, just in
case.

Second, copy the new, improved sendmail config that you've just
edited to /usr/lib/sendmail.cf

Third, if you're using the frozen config file stuff (this is something
that saves time on sendmail start up, look for a non-zero length file
name /usr/lib/sendmail.fc), run /usr/lib/sendmail -bz (to re-freeze the
new config file; note that if you use frozen config files, when ever
you make a change to your config file you have to do this)

Forth, kill the sendmail daemon that is offering SMTP service to the
network (look for a sendmail process with a PID typically less than
200, and kill it), and restart it with the same arguments as in
/etc/rc.local (usually, -bd -q30m, which means "run in daemon mode,
offer SMTP service to the network, and do a queue run every 30
minutes). The reason that you have to do this is that sendmail reads
its configuration file once upon start up, and so the daemon offering
SMTP service is still using the old config file, despite the fact that
you've installed a new one.

You're done. You have a new sendmail configuration file installed and
operating which will handle fully qualified domain names in /etc/hosts.

If you have problems with this configuration file, please drop a note
to me, Erik Fair, at <fair@ucbarpa.berkeley.edu>, and be sure to
include headers of errant messages in your problem report. I give no
guarantee of merchantability, fitness for particular purpose or
warrantee, but I will *try* to help if you have a problem.

	Erik E. Fair	ucbvax!fair	fair@ucbarpa.berkeley.edu

	April 3, 1987

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