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6. Installing Transport Software

6.1 Qmail v1.03

Secured, fast and easy to use, this is my preferred MTA (mail transport agent).

Currently, no distribution comes with qmail preinstalled. We will focus on compiling and installing qmail, since this is the only tricky part: configuration is really straightforward.

Getting qmail

Go to www.qmail.org to download the latest version.

Uncompressing sources

Then decompress it by running:

mv qmail.tar.gz /usr/local/src
cd /usr/local/src ; tar -zxvf qmail.tar.gz

If you find a bz2 version (new and better compression format), just replace tar with:

bunzip2 qmail.tar.bz2
tar -xvf qmail.tar

Preparing for compilation

Now enter the qmail directory to examine the configuration defaults:

cd qmail; more conf-*

You shouldn't need to change any defaults, but you could (for example) specify an alternate installation directory or better compilation flags.

Now run:

mkdir /var/qmail

to create target dir.

If you haven't installed a Debian distribution, you'll need to add several user IDs for qmail's use: qmail's high security depends on that.

The fact that qmail is divided into modules running each under their own UID makes it much harder for an intruder to break your whole mail system or gain root access by abusing it.

So run:

   # groupadd nofiles
   # useradd -g nofiles -d /var/qmail/alias alias
   # useradd -g nofiles -d /var/qmail qmaild
   # useradd -g nofiles -d /var/qmail qmaill
   # useradd -g nofiles -d /var/qmail qmailp
   # groupadd qmail
   # useradd -g qmail -d /var/qmail qmailq
   # useradd -g qmail -d /var/qmail qmailr
   # useradd -g qmail -d /var/qmail qmails

or hand-edit /etc/passwd and /etc/group to add these users by yourself.

Evan E. reported he had to use "-g groupid" parameter for a vanilla groupadd (Caldera 1.2), else groupadd reported this error : "A group with that name already exists."

For example you can respectively add:

        qmail:*:2107:
        nofiles:*:2108:

&

        alias:*:7790:2108::/var/qmail/alias:/bin/true
        qmaild:*:7791:2108::/var/qmail:/bin/true
        qmaill:*:7792:2108::/var/qmail:/bin/true
        qmailp:*:7793:2108::/var/qmail:/bin/true
        qmailq:*:7794:2107::/var/qmail:/bin/true
        qmailr:*:7795:2107::/var/qmail:/bin/true
        qmails:*:7796:2107::/var/qmail:/bin/true

Now you can run

make setup check

to check your configuration, then :

./config

to configure qmail.

Attention, your server has to be resolvable by DNS or ./config will get confused.

If you don't have DNS access, you can give your server name directly via :

./config-fast foo.bar.com

Now you must install some aliases, since /etc/alias is not used by qmail unless you compile and install an optional package.

Here's my setup :

File : ".qmail-MAILER-DAEMON"
&postmaster
File : ".qmail-bin"
&root
File : ".qmail-daemon"
&root
File : ".qmail-decode"
&root
File : ".qmail-dumper"
&root
File : ".qmail-games"
&root
File : ".qmail-ingres"
&root
File : ".qmail-mailer-daemon"
&postmaster
File : ".qmail-manager"
&root
File : ".qmail-news"
&root
File : ".qmail-nobody"
&root
File : ".qmail-operator"
&root
File : ".qmail-postmaster"
&root
File : ".qmail-root"
&guylhem
File : ".qmail-system"
&root
File : ".qmail-toor"
&root
File : ".qmail-uucp"
&root
File : ".qmail-uucp-default"
|preline -dr /usr/bin/uux - -r -gC -a"${SENDER:-MAILER-DAEMON}" lm!rmail "($DEFAULT@$HOST)"

You need to create each of these file in ~alias, replacing &guylhem in .qmail-root by your own login to get root mail.

ATTENTION UUCP USERS !

DO NOT TRUST THE QMAIL FAQ FOR UUCP, USE MY .qmail-uucp-default INSTEAD! ELSE YOU WILL NOT BE ABLE TO SEND ANY MAIL BY YOUR UUCP CONNEXION!

Now you'll need to decide in which format your users will get their mail.

Here's my suggestion :

To fix the default format, read each file in /var/qmail/boot then copy the one you best like to /var/qmail/rc.

home or proc are safe choices, but prefer home for security reasons.

Configuring qmail

In /var/qmail/control, edit:

defaultdomain, me, plusdomain

These 3 examples show you the power and ease of configuration of qmail!

locals, rcpthosts

If you want to support virtual domain names, just put additional names in these files. Any mail you receive for these names will be handled locally.

The difference between locals and rcpthosts is the latter isn't considered as a local alias, which is useful if you receive mail from some free email address like yahoo.com or lemel.fr while you also send mail to other users of these non local services, i.e. you don't want to handle locally mail send to someone@yahoo.com!

virtualdomains

There can you specify default outgoing mode, for example :

#:alias-uucp

if you don't want to send outgoing mail by uucp but by smtp (default) or

:alias-ucp

if you send your outgoing mail by uucp.

Testing qmail

Now it is configured, try:

sh -cf '/var/qmail/rc &'

to launch qmail (it won't interfere with your local MTA), then:
echo to: mylogin | /var/qmail/bin/qmail-inject

You should receive this mail in the format you've chosen in /var/qmail/boot/.

Removing your other MTA

If this test was successful, just kill your previous MTA:

killall -STOP daemon_name ; if any children are running, you should killall -CONT their_name, wait, killall -STOP again, and repeat ad nauseam.

If there aren't any children, killall -TERM and then killall -CONT.

Remove it (how you can do this depends on the distribution you installed, for example rpm -e --nodeps on RedHat, Caldera and Suse, or dpkg -r --force-depends on Debian) then run:

# ln -s /var/qmail/bin/sendmail /usr/lib/sendmail
# ln -s /var/qmail/bin/sendmail /usr/sbin/sendmail

Now set up qmail-smtpd in /etc/inetd.conf (all on one line):

smtp stream tcp nowait qmaild /var/qmail/bin/tcp-env tcp-env /var/qmail/bin/qmail-smtpd

If you are using a old non-SYSV-init distribution like redhat, just add to your boot scripts:

sh -cf '/var/qmail/rc &' 

Usually this should be /etc/rc.local but your mileage may vary.

For actual SYSV-init compliant distributions (RedHat, Caldera, Suse, Debian), add this script to /etc/init.d/ or /etc/rc.d/init.d/ :

DEBIAN version:

#!/bin/sh

test -x /var/qmail/rc || exit 0

case "$1" in
  start)
     echo -n "Starting mta: "
     sh -cf '/var/qmail/rc &'
     echo "qmail."
     ;;
  stop)
     echo -n "Stopping mta: "
     killall qmail-lspawn
     echo "qmail."
     ;;
  restart)
     echo -n "Restarting mta: "
     killall -HUP qmail-lspawn
     killall -ALRM qmail-lspawn
     echo "qmail."
     ;;
  *)
     echo "Usage: /etc/init.d/qmail {start|stop|restart}"
     exit 1
esac

exit 0

REDHAT version:

#!/bin/sh
#
# qmail      This shell script takes care of starting and stopping qmail.
#
# description: qmail is a Mail Transport Agent, which is the program \
#              that moves mail from one machine to another.
# processname: qmail
# config: /var/qmail/control/

# Source function library.
. /etc/rc.d/init.d/functions

# Source networking configuration.
. /etc/sysconfig/network

export PATH=$PATH:/var/qmail/bin

# Check that networking is up.
[ ${NETWORKING} = "no" ] && exit 0

[ -f /usr/sbin/sendmail ] || exit 0

# See how we were called.
case "$1" in
  start)
        # Start daemons.
        echo -n "Starting qmail: "
        qmail-start '|preline procmail' splogger qmail &
        touch /var/lock/subsys/qmail
        echo
        ;;
  stop)
        # Stop daemons.
        echo -n "Shutting down qmail: "
        killproc qmail-lspawn
        echo
        rm -f /var/lock/subsys/qmail
        ;;
  restart)
        $0 stop
        $0 start
        ;;
  status)
        status qmail
        ;;
  *)
        echo "Usage: qmail {start|stop|restart|status}"
        exit 1
esac

exit 0

And make symlinks to each /etc/rc.d/rcN.d/, for example:

ln -sf /etc/init.d/qmail /etc/rc1.d/K19qmail

If the first letter is K, you will kill qmail on this runlevel (1 for single mode or 6 for boot), but if the first letter is S, you will start qmail on this runlevel (each others runlevel).

RedHat, Caldera and Suse will use /etc/rc.d/ instead of plain /etc/ for Debian distribution, i.e. /etc/rc.d/rc1.d or /etc/rc.d/init.d for example.

That's all, folks!

No need to reboot (remember, you're using linux, not some other cheap OS!) for the modifications to take effect, just run:

killall inetd
init 1

To go to single user mode, then:

init 2

to go back to your default runlevel (indicated in /etc/inittab with initdefault label).

You could also hand-start qmail script but "init" method will show you if qmail script is well positioned, i.e. launched after network scripts but before any program which depends on email to warn you (like inn).

6.2 Smail v3.1

Smail3.1 seems to be a de-facto standard transport agent for uucp-only sites and for some smtp sites. It's easy to configure, it compiles without patching from the sources and it's fairly secure.

Configuring smail

Install the smail binary from your distribution (I recommend you choose this) or get the smail sources and build smail. If you're building smail from sources, you need to have the following in your os/linux file so that 'sed' gives you shell scripts that work properly.

CASE_NO_NEWLINES=true 

Once it's installed, config. files will certainly go in /etc/smail (but your mileage may vary if you use old distributions); let's start editing them!

"config" file

# From
smart_path=polux
smart_transport=uux

# To
hostname=barberouge
domains=linux.lmm.com

visible_name=barberouge.linux.lmm.com
uucp_name=barberouge.linux.lmm.com

# max_message_size=512k
# auth_domains=foo.bar
# more_hostnames=barberouge.polux.freenix.fr

Well, first, who is feeding you? I'm fed by "polux" via uucp (i.e. uux transport); naturally you need to change this file according to your own situation. For example, you could by fed by "bargw.bar.foobar.com" via "smtp", in that case you don't need a transport file and can define "-transport_file " to indicate you don't need one.

You can also use "postmaster_address = yourname", hide the network topology in outgoing addresses (if you're a gateway) using "visible_name", set which aliases address can also be used for the email you receive, using "more_hostnames".

See smail documentation for more details or the examples in /usr/doc/smail/examples to see if any match your situation.

"directors" file

# aliasinclude - expand ":include:filename" addresses produced by alias files
# This entry and the next one are pretty much boiler-plate.  Reasons
# for making significant changes are few.  The sole purpose of these
# is to match and expand addresses of the form:
#       :include:pathname
# which may occur in alias files or mailing-list/forward files
# (produced by any director with a driver of forwardfile).
aliasinclude:
        driver = aliasinclude,          # use this special-case driver
        nobody;                         # associate nobody user with addresses
                                        #  when mild permission violations
                                        #  are encountered
        copysecure,                     # get permissions from alias director
        copyowners,                     # get owners from alias director



# forwardinclude - expand ":include:filename" addrs produced by forward files
forwardinclude:
        driver = forwardinclude,        # use this special-case driver
        nobody;
        copysecure,                     # get perms from forwarding director
        copyowners,                     # get owners from forwarding director


# aliases - search for alias expansions stored in a database
# This is the standard aliases file.  It is used for generic things,
# like mapping root, postmaster, MAILER-DAEMON and uucp to site
# admins, creating some small system alias expansions, and such.  In
# this site configuration, the aliases file is used mostly for
# machine-specific aliasing/forwarding information.  Global forwarding
# information should be put in the "forward" database.
aliases:
        driver=aliasfile,               # general-purpose aliasing director
        -nobody,                        # all addresses are associated
                                        # with nobody by default, so setting
                                        # this is not useful.
        sender_okay,                    # don't remove sender from expansions
        owner=owner-$user;              # problems go to an owner address
        file=/etc/aliases,
        modemask=002,                   # should not be globally writable
        optional,                       # ignore if file does not exist
        proto=lsearch,                  # unsorted ASCII file


# forward - search for expansions stored in a forwarding database
# This is the subdomain-wide user forwarding database.  Entries are
# maintained here for current or past users, to forward their mail to
# their preferred mail-reading machine.  The forward database is
# shipped around the TCP/IP network as changes are made, to keep the
# network consistent.
#forward:
#       driver = aliasfile,             # general-purpose aliasing director
#       -nobody,                        # all addresses are associated
#                                       # with nobody by default, so setting
#                                       # this is not useful.
#       owner = real-$user;             # problems go to an owner address
#
#       file = /etc/forward,
#       modemask = 002,
#       proto = dbm,                    # use dbm(3X) library for access


# dotforward - expand .forward files in user home directories
# For users that have an entry in the "forward" database, a ".forward"
# file is only used if it is on the "home" machine, as identified in
# the forward database.  If used, it is treated as a list of addresses
# to which mail should be delivered, rather than (or in addition to)
# the user identified in the local address.
dotforward:
        driver = forwardfile,           # general-purpose forwarding director
        owner = postmaster, nobody, sender_okay;

        file = ~/.forward,              # .forward file in home directories
        checkowner,                     # the user can own this file
        owners = root,                  # or root can own the file
        modemask = 002,                 # it should not be globally writable
        caution = daemon:root,          # don't run things as root or daemon
        # be extra careful of remotely accessible home directories
        unsecure = "~uucp:/tmp:/usr/tmp:/var/tmp"


# forwardto - expand a "Forward to " in user mailbox files
# This emulates the V6/V7/System-V forwarding mechanism which uses a
# line of forward addresses stored at the beginning of user mailbox files
# prefixed with the string "Forward to "
forwardto:
        driver = forwardfile,
        owner = postmaster, nobody, sender_okay;

        file = /var/spool/mail/${lc:user},      # point at user mailbox files
        forwardto,                      # enable "Forward to " function
        checkowner,                     # the user can own this file
        owners = root,                  # or root can own the file
        modemask = 0002,                # under System V, group mail can write
        caution = daemon:root           # don't run things as root or daemon


# user - match users on the local host with delivery to their mailboxes
user:   driver = user;                  # driver to match usernames
        transport = local               # local transport goes to mailboxes


# real_user - match usernames when prefixed with the string "real-"
# This is useful for allowing an address which explicitly delivers to a
# user's mailbox file.  For example, errors in a .forward file expansion
# could be delivered here, or forwarding loops between multiple machines
# can be resolved by using a real-username address.  Also, users that
# wish to use mail as a means of transferring data to a machine that
# is not their "home" machine can mail to real-login-name@remote.host.
real_user:
        driver = user;
        transport = local,
        prefix = "real-"                # for example, match real-root


# lists - expand mailing lists stored in a list directory
# mailing lists can be created simply by creating a file in the
# /etc/smail/lists directory.
lists:  driver = forwardfile,
        caution,                        # flag all addresses with caution
        nobody,                         # and then associate the nobody user
        owner = owner-$user;            # system V sites may wish to use
                                        # o-$user, as owner-$user may be
                                        # too long for a 14-char filename.
        file = lists/${lc:user}         # lists is under $smail_lib_dir


# owners - expand mailing lists stored in a list owner directory
# mailing lists owner lists can be created simply by creating a file
# in the /etc/smail/lists/owner directory.  Mailing list owners
# are sent locally generated errors dealing with a mailing list of the
# same name.  To create an owner list for a mailing list, create a
# file with the name of the list in /etc/smail/lists/owner.  This
# will create a list address of owner-listname, as is used by the
# "lists" director above.
owners: driver = forwardfile,
        caution,                        # flag all addresses with caution
        nobody,                         # and then associate the nobody user
        owner = postmaster;             # system V sites may wish to use
                                        # o-$user, as owner-$user may be
                                        # too long for a 14-char filename.
        prefix = "owner-",
        file = lists/owner/${lc:user}   # lists is under $smail_lib_dir


# request - expand mailing lists stored in a list request directory
# mailing lists request lists can be created simply by creating a file
# in the /etc/smail/lists/request directory.  Request addresses
# are typically used as a standard address for queries about a mailing
# list.  For example, requests for additions or deletions to a list
# will generally be sent to "list-request", which should be set up to
# forward to the appropriate person or persons.
request: driver = forwardfile,
        caution,                        # flag all addresses with caution
        nobody,                         # and then associate the nobody user
        owner = postmaster;             # system V sites may wish to use
                                        # o-$user, as owner-$user may be
                                        # too long for a 14-char filename.
        suffix = "-request",
        file = lists/request/${lc:user} # lists is under $smail_lib_dir

You shouldn't need to change anything here, only mailing list options if you intend to run some using smail, or forwards options if, for example, you want to disable forwarding.

"fidopaths" file

.f105.n324.z2.fidonet.org       f105.n324.z2.fidonet.org!%s
.n324.z2.fidonet.org            f105.n324.z2.fidonet.org!%s
.z2.fidonet.org                 f105.n324.z2.fidonet.org!%s
.fidonet.org                    f105.n324.z2.fidonet.org!%s

Create such a file only if you're using ifmail and FIDO.

"routers" file

# forces - force certain paths
# This database exists as a means of hardcoding the paths to various
# machines or domains.  It is for use in creating temporary tweaks to
# the other routing databases.  To change the database, edit the file
# maps/force.path and type "make" in the maps/ subdirectory.
forces:
        driver = pathalias,             # router to search paths file
        method = /etc/smail/maps/table; # transports are in this file
        file = forcepaths,              # file containing force path info
        proto = lsearch,                # use the sorted path file
        optional,
        reopen                          # close when not being used


uucp_neighbors:
        driver=uuname,                  # use a program which returns neighbors
        transport=uux;
        cmd="/usr/bin/uuname -a",       # specifically, use the uuname program
#        domain=uucp                    # strip ending ".uucp"


# smart_host - a partially specified smarthost director
# If the config file attribute smart_path is defined as a path from the
# local host to a remote host, then hostnames not matched otherwise will
# be sent off to the stated remote host.  The config file attribute
# smart_transport can be used to specify a different transport.
# If the smart_path attribute is not defined, this router is ignored.
smart_host:
        driver = smarthost,             # special-case driver
        transport = uux                 # by default deliver over UUCP
#       path=phreak


# ifmail - to send mails to fidonet and vice versa
ifmail:
        driver=pathalias,
        transport=ifmail;
        file=fidopaths,
        proto=lsearch

You should only include ifmail chapter if you use ifmail for FIDO mails. Note you can also change transport mode from "uux" (ie UUCP) to, for example, "smtp" or even 'hardcode the paths to various machines or domains' in "/etc/smail/maps/table".

This is useful if you want outgoing mail for your local network to be delivered immediately, since there's no need for it to be routed to your uucp connexion of your internet access.

"transports" file

# local - deliver mail to local users
# Tell smail to append directly to user mailbox files in the /var/spool/mail
# directory.
#local: driver = appendfile,            # append message to a file
#       -return_path,                   # include a Return-Path: field
#       local,                          # use local forms for delivery
#       from,                           # supply a From_ envelope line
#       unix_from_hack;                 # insert > before From in body
#
#       file = /var/spool/mail/${lc:user},      # use this location for Linux
#                                               # Note, mail spool must be 1777
#       file = ~/mailfile,              # use this location for better security
#       group = mail,                   # group to own file for System V
#       mode = 0660,                    # under System V, group mail can access
#       suffix = "\n",                  # append an extra newline
#       append_as_user,


# This allows each user to have a ~/.procmailrc file to control filtering
# of mail and saving mail from mail lists in separate mailboxes if they wish.
local:  +inet,
        -uucp,
        driver = pipe,                  # append message to a file
        return_path,                    # include a Return-Path: field
        local,                          # use local forms for delivery
        from,                           # supply a From_ envelope line
        unix_from_hack;                 # insert > before From in body

        cmd = "/usr/bin/procmail",      # use procmail for local delivery
        parent_env,                     # environment info from parent addr
        pipe_as_user,                   # use user-id associated with address
        umask = 0022,                   # umask for child process
#       -ignore_status,                 # exit status should be believed
#       -ignore_write_errors,           # retry on broken pipes


# pipe - deliver mail to shell commands
# This is used implicitly when smail encounters addresses which begin with
# a vertical bar character, such as "|/usr/lib/news/recnews talk.bizarre".
# The vertical bar is removed from the address before being given to the
# transport.
#pipe:  driver = pipe,                  # pipe message to another program
#       return_path, local, from, unix_from_hack;
#
#       cmd = "/bin/sh -c $user",       # send address to the Bourne Shell
#       parent_env,                     # environment info from parent addr
#       pipe_as_user,                   # use user-id associated with address
#       umask = 0022,                   # umask for child process
#       -log_output,                    # do not log stdout/stderr
#       ignore_status,                  # exit status may be bogus, ignore it
#       ignore_write_errors,            # ignore broken pipes


# file - deliver mail to files
# This is used implicitly when smail encounters addresses which begin with
# a slash or squiggle character, such as "/usr/info/list_messages" or
# perhaps "~/Mail/inbox".
#file:  driver = appendfile,
#       return_path, local, from, unix_from_hack;
#
#       file = $user,                   # file is taken from address
#       append_as_user,                 # use user-id associated with address
#       expand_user,                    # expand ~ and $ within address
#       check_path,
#       suffix = "\n",
#       mode = 0644


# uux - deliver to the rmail program on a remote UUCP site
#
# As many as five recipient addresses will be delivered to the remote
# host in one UUCP transaction.
uux:    driver = pipe,
        -uucp,
        inet,
#       uucp,                           # use UUCP-style addressing forms
        from,                           # supply a From_ envelope line
        max_addrs = 5,                  # at most 5 addresses per invocation
        max_chars = 200;                # at most 200 chars of addresses
# the -r flag prevents immediate delivery, parentheses around the
# $user variable prevent special interpretation by uux.
        cmd = "/usr/bin/uux - -r -g$grade $host!rmail $((${strip:user})$)",
#        cmd="/usr/bin/uux - $host!rmail $(($user)$)",
        ignore_write_errors,            # ignore broken pipes
        umask = 0022,
#       pipe_as_sender,


# uux_one_addr - deliver mail over UUCP to a remote host that can take
#                one address at a time.
# This is often necessary when delivering to a site running an unmodified
# version of 4.1BSD.
uux_one_addr:
        driver = pipe,
        uucp,                           # use UUCP-style addressing forms
        from;                           # supply a From_ envelope line
# the -r flag prevents immediate delivery
        cmd = "/usr/bin/uux - -r -g$grade $host!rmail (${strip:user})",
        umask = 0022,
        pipe_as_sender


queueonly:
        driver = pipe;                  # send the message to a pipe
        cmd = "/usr/lib/sendmail -Q -f $sender -bm $user",
                                        # use getmail for local delivery
        user=root,                      # execute getmail as "root"
        group=mail,                     # execute getmail as "mail"
        parent_env,                     # environment info from parent addr
        -pipe_as_user,                  # use user-id associated with address
        umask = 0007,                   # umask for child process
 
# to deliver the message.  The smtp transport is included only if BSD
# networking exists.
# The uucp attribute can be specified for transfers within the UUCP
# zone.  The inet attribute must be specified for transfers within the
# Internet.
# NOTE: This is hardly optimal, a backend should exist which can handle
#       multiple messages per connection.
# ALSO: It may be necessary to restrict max_addrs to 100, as this is the
#       lower limit SMTP requires an implementation to handle for one
#       message.
smtp:   driver=tcpsmtp,
        inet,                           # if UUCP_ZONE is not defined
#       uucp,                           # if UUCP_ZONE is defined
        -max_addrs, -max_chars;         # no limit on number of addresses

        short_timeout=5m,               # timeout for short operations
        long_timeout=2h,                # timeout for longer SMTP operations
        service=smtp,                   # connect to this service port
# For internet use: uncomment the below 4 lines
       use_bind,                       # resolve MX and multiple A records
       defnames,                       # use standard domain searching
       defer_no_connect,               # try again if the nameserver is down
       local_mx_okay,                  # fail an MX to the local host


ifmail:
        from,received,max_addrs=5,max_chars=200,
        driver=pipe;
        pipe_as_sender,
        cmd="/usr/local/bin/ifmail -x9 -r$host $((${strip:user})$)"

You should include an ifmail chapter only if you use ifmail for FIDO mail. Apart from that, you shouldn't need to edit anything in this file which defines transport agents (like uux, smtp ...) you can use as parameters in other config. files.

Note I commented out some parts, like "pipes" or "file", to enhance security.

"maps/" directory

It contains map and table files:

First, map file

#N      foo.bar foo2.bar2
#S      AT 486/RedHat Linux 1.2.13
#O      organization
#C      contact
#E      administration (email)
#T      phone
#P      address
#R
#U      hosts connected via uucp
#W      created/edited by
#
hname polux

hname linux.eu.org

hname = polux
hname = polux.linux.eu.org

Once again, edit this file to match you situation (I'm fed by polux.linux.eu.org).

Now table file

 
*       uux

You can define different transports to different paths, for example "smtp" for the machines in your local network, "uux" (i.e. uucp) for the rest of the world or vice-versa (I'm using uucp for any outgoing mail, therefore I use "*"!).

Other good examples

The previous files are the one I currently use for my site, you shouldn't encounter any problem using them as samples/basis for your own files.

The following files are provided only as good examples to configure smail a different way.

#ident "@(#) transports,v 1.2 1990/10/24 05:20:46 tron Exp"

# See smail(5) for a complete description of the contents of this file.

# local - deliver mail to local users
#
# Tell smail to append directly to user mailbox files in the /usr/mail
# directory.
local:  driver = appendfile,            # append message to a file
        return_path,                    # include a Return-Path: field
        local,                          # use local forms for delivery
        from,                           # supply a From_ envelope line
        unix_from_hack;                 # insert > before From in body

        file = /usr/mail/${lc:user},    # use this location for System V
        group = mail,                   # group to own file for System V
        mode = 0660,                    # under System V, group mail can access
        suffix = "\n",                  # append an extra newline
        append_as_user,

# pipe - deliver mail to shell commands
#
# This is used implicitly when smail encounters addresses which begin with
# a vertical bar character, such as "|/usr/lib/news/recnews talk.bizarre".
# The vertical bar is removed from the address before being given to the
# transport.
pipe:   driver = pipe,                  # pipe message to another program
        return_path, local, from, unix_from_hack;

        cmd = "/bin/sh -c $user",       # send address to the Bourne Shell
        parent_env,                     # environment info from parent addr
        pipe_as_user,                   # use user-id associated with address
        umask = 0022,                   # umask for child process
        -log_output,                    # do not log stdout/stderr
        ignore_status,                  # exit status may be bogus, ignore it
        ignore_write_errors,            # ignore broken pipes

# file - deliver mail to files
#
# This is used implicitly when smail encounters addresses which begin with a
# slash or squiggle character, such as "/usr/info/list_messages" or perhaps
# "~/Mail/inbox".
file:   driver = appendfile,
        return_path, local, from, unix_from_hack;

        file = $user,                   # file is taken from address
        append_as_user,                 # use user-id associated with address
        expand_user,                    # expand ~ and $ within address
        suffix = "\n",
        mode = 0644

# uux - deliver to the rmail program on a remote UUCP site
#
# As many as five recipient addresses will be delivered to the remote host in
# one UUCP transaction.
uux:    driver = pipe,
        uucp,                           # use UUCP-style addressing forms
        from,                           # supply a From_ envelope line
        max_addrs = 5,                  # at most 5 addresses per invocation
        max_chars = 200;                # at most 200 chars of addresses

        # the -r flag prevents immediate delivery, parentheses around the
        # $user variable prevent special interpretation by uux.
        cmd = "/usr/bin/uux - -r -g$grade $host!rmail $((${strip:user})$)",
        umask = 0022,
        pipe_as_sender

# uux_one_addr - deliver mail over UUCP to a remote host that can take one
# address at a time.
#
# This is often necessary when delivering to a site running an unmodified
# version of 4.1BSD.
uux_one_addr:
        driver = pipe,
        uucp,                           # use UUCP-style addressing forms
        from;                           # supply a From_ envelope line

        # the -r flag prevents immediate delivery
        cmd = "/usr/bin/uux - -r -g$grade $host!rmail (${strip:user})",
        umask = 0022, pipe_as_sender

# demand - deliver to a remote rmail program, polling on demand
demand: driver = pipe,
        uucp, from, max_addrs = 5, max_chars = 200;

        # with no -r flag, try to contact remote site immediately
        cmd = "/usr/bin/uux - -g$grade $host!rmail $(($user)$)",
        umask = 0022, pipe_as_sender

# uusmtp - deliver to the rsmtp program on a remote UUCP site
#
# Deliver using a simple Batched SMTP protocol to the remote machine.
# This allows much more arbitrary addresses to be used.  It also
# removes the limit on recipient addresses per invocation of uux.
uusmtp: driver = pipe,
        bsmtp,                          # send batched SMTP commands
        -max_addrs,                     # there is no limit on the number or
        -max_chars;                     #   total size of recipient addresses.

        # supply -r to prevent immediate delivery, the recipient addresses
        # are stored in the data sent to the standard input of rsmtp.
        cmd = "/usr/bin/uux - -r -g$grade $host!rsmtp",
        umask = 0022, pipe_as_sender

# demand_uusmtp - deliver to a remote rsmtp program, polling on demand
demand_uusmtp:
        driver = pipe,
        bsmtp, -max_addrs, -max_chars;

        # with no -r flag, try to contact remote site immediately
        cmd = "/usr/bin/uux - -g$grade $host!rsmtp",
        umask = 0022, pipe_as_sender

# smtp - deliver using SMTP over TCP/IP
#
# Connect to a remote host using TCP/IP and initiate an SMTP conversation to
# deliver the message.  The smtp transport is included only if BSD networking
# exists.

# NOTE: It may be necessary to restrict max_addrs to 100, as this is the
#       lower limit SMTP requires an implementation to handle for one
#       message.
smtp:   driver = smtp,
        -max_addrs,
        -max_chars

#ident "@(#) table,v 1.2 1990/10/24 05:20:31 tron Exp"

# This file names the transports that are to be used in delivering
# to specific hosts from bargw.

#host           transport
#--------       ---------
curdsgw         demand_uusmtp   # deliver using batched SMTP
oldbsd          uux_one_addr    # 4.1BSD sites cannot take more than one addr
sun             demand          # call sun when their is mail to send
*               uux             # for all others, poll at intervals

Restarting inetd

To run smail as a smtp daemon, add one of the following to /etc/inetd.conf:

         smtp stream tcp nowait  root  /usr/bin/smtpd smtpd

or:

         smtp stream tcp nowait  root  /usr/sbin/tcpd  /usr/sbin/in.smtpd

Outgoing mail gets sent automatically, when using elm.

Smail with smtp

Generally, ISPs use smtp, therefore you shouldn't have any problems sending your mail. If your internet link is down when you send mail, then the mail sits in "/var/spool/smail/input". When the link next comes up, "runq" is run which causes the mail to be sent. However, receiving mail is the problem since your provider has many clients to look after, not only you!

Usually, you can retrieve your mail via the POP protocol, see POP section below.

6.3 OUTDATED SECTION: Sendmail+IDA

For big sites, sendmail is worth choosing, due to the "incredible ease of use", (very relative feeling when you know qmail) but you must decide which you want between sendmail+IDA and sendmail 8.x:

Remember, linux newbies or people concerned by security / ease of configuration should rather try using smail or qmail, which are easier to use and safer.

Source installation

If your distribution doesn't provide you with a ready-to-install sendmail package (.rpm for RedHat, Caldera and Suse, .deb for Debian) just download the sources and run:

Edit out the distributed hostname, aliases, smarthost and put in the correct one for your site. The default file is for a uucp-only site (no longer in 8.x) who has domainized headers and who talks to a smart host. Then "make yourhostname.cf" and move the resulting file to /etc/sendmail.cf

You'll just have to touch the files so that the Makefile works. Just edit the .m4 file, make sendmail.cf and start testing it.

You should also update your version to at least 5.67b since there is a nasty security hole in 5.67a and earlier. Another nice thing is that if you have mail.debug set and you run syslogd, your incoming and outgoing mail messages will get logged. See the "/etc/syslog.conf" file for details.

The sources for sendmail+IDA can be found at vixen.cso.uiuc.edu ; they require no patching to run under Linux if you're running something like a kernel of 1.00.

If you're running a kernel > 1.1.50, you get the fun of reversing most of the Linux-specific patches that are now in the vanilla sources. (I *did* told you this sendmail was only for old kernels:-)

It's extremely obvious where this needs to be done: just type "make" and when it blows up, go to that line in the sources and comment out the Linux-specific code that's in there.

If you're going to run sendmail+IDA, I strongly recommend you go to the sendmail5.67b+IDA1.5 version since all required Linux-specific patches are now in the vanilla sources and several security holes have been plugged that WERE (!!!) in the older version you may have grabbed or built before about December 1st, 1993.

Now linux kernel is 2.0, you should use sendmail 8.x instead of sendmail+IDA, but I already told you'd better choose sendmail 8.x:-)

The sendmail.m4 file

Sendmail+IDA requires you to set up a sendmail.m4 file rather than editing the sendmail.cffile directly. The nice thing about this is that it is simple to set up mail configurations that are extremely difficult (if not totally impossible for most people to set up correctly) in smail or traditional sendmail.

The sendmail.m4 file that corresponds to the above smail example looks like the following:

  dnl #------------------ SAMPLE SENDMAIL.M4 FILE ------------------
  dnl #
  dnl # (the string 'dnl' is the m4 equivalent of commenting out a line)
  dnl # (well, not exactly, but use it for this purpose if you must :-)
  dnl # you generally don't want to override LIBDIR from the compiled in paths
  dnl #define(LIBDIR,/usr/local/lib/mail)dnl    # where all support files go
  define(LOCAL_MAILER_DEF, mailers.linux)dnl    # mailer for local delivery
  define(POSTMASTERBOUNCE)dnl                   # postmaster gets bounces
  define(PSEUDODOMAINS, BITNET UUCP)dnl         # don't try DNS on these
  dnl #
  dnl #-------------------------------------------------------------
  dnl #
  dnl # names we're known by
  define(PSEUDONYMS, myhostname.subdomain.domain myhostname.UUCP)
  dnl #
  dnl # our primary name
  define(HOSTNAME, myhostname.subdomain.domain)
  dnl #
  dnl # our uucp name
  define(UUCPNAME, myhostname)dnl
  dnl #
  dnl #-------------------------------------------------------------
  dnl #
  define(UUCPNODES, |uuname|sort|uniq)dnl       # our uucp neighbors
  define(BANGIMPLIESUUCP)dnl                    # make certain that uucp
  define(BANGONLYUUCP)dnl                       #  mail is treated correctly
  define(RELAY_HOST, my_uucp_neighbor)dnl       # our smart relay host
  define(RELAY_MAILER, UUCP-A)dnl               # we reach moria via uucp
  dnl #
  dnl #--------------------------------------------------------------------
  dnl #
  dnl # the various dbm lookup tables
  dnl #
  define(ALIASES, LIBDIR/aliases)dnl            # system aliases
  define(DOMAINTABLE, LIBDIR/domaintable)dnl    # domainize hosts
  define(PATHTABLE, LIBDIR/pathtable)dnl        # paths database
  define(GENERICFROM, LIBDIR/generics)dnl       # generic from addresses
  define(MAILERTABLE, LIBDIR/mailertable)dnl    # mailers per host or domain
  define(UUCPXTABLE, LIBDIR/uucpxtable)dnl      # paths to hosts we feed
  define(UUCPRELAYS, LIBDIR/uucprelays)dnl      # short-circuit paths
  dnl #
  dnl #--------------------------------------------------------------------
  dnl #
  dnl # include the 'real' code that makes it all work
  dnl # (provided with the source code)
  dnl #
  include(Sendmail.mc)dnl                         # REQUIRED ENTRY!!!
  dnl #
  dnl #------------ END OF SAMPLE SENDMAIL.M4 FILE -------
 

Defining a local mailer

Unlike most Unix distributions, Linux did not come with a local mail delivery agent by default.

Slackware did! Well at least it is offered by the easy-to-use-but-longwinded installation script. It uses procmail.

Now, deliver or procmail is generally installed, with a default sendmail setup to handle local mail, so no complexity will be added to this already very complex setup. I recommend using the commonly available deliver or procmail programs, which can be optional packages in a some Linux distributions.

In order to do so, you need to define a LOCAL_MAILER_DEF in the sendmail.m4 file that points to a file that looks like:

  # -- /usr/local/lib/mail/mailers.linux --
  #     (local mailers for use on Linux )
  Mlocal, P=/usr/bin/deliver, F=SlsmFDMP, S=10, R=25/10, A=deliver $u
  Mprog,  P=/bin/sh,       F=lsDFMeuP,   S=10, R=10, A=sh -c $u

There is a also built-in default for deliver in the Sendmail.mc file that gets included into the sendmail.cf file. To specify it, you would not use the mailers.linux file but would instead define the following in your sendmail.m4 file:

   dnl --- (in sendmail.m4) ---
   define(LOCAL_MAILER_DEF, DELIVER)dnl       # mailer for local delivery

Unfortunately, Sendmail.mc assumes deliver is installed in /bin, which is not the case with Slackware1.1.1 (which installs it in /usr/bin). In that case you'd need to either fake it with a link or rebuild deliver from sources so that it resides in /bin. Please note procmail is generally better than deliver, for example for mail filtering.

The sendmail+IDA dbm tables

Setting up special behavior for sites or domains is done through a number of optional dbm tables rather than editing the sendmail.cf file directly.

Refer to the July-1994 issue of Linux Journal (if you can still find it:-), to the docs in the sources, or to the sendmail chapter in the newest version of the Linux Documentation Project Networking Administration Guide which will be available real-soon-now for more details.

So which entries are really required?

When not using any of the optional dbm tables, sendmail delivers mail via the RELAY_HOST and RELAY_MAILER) defined in the sendmail.m4 file used to generate sendmail.cf. It is easily possible to override this behavior through entries in the domaintable or uucpxtable.

A generic site that is on Internet and speaks Domain Name Service, or one that is UUCP-only and forwards all mail via UUCP through a smart RELAY_HOST, probably does not need any specific table entries at all.

Virtually all systems should set the DEFAULT_HOST and PSEUDONYMS macros, which define the canonical site name and aliases it is known by.

If all you have is a relay host and relay mailer, you don't need to set these defaults since it works automagically. UUCP hosts will probably also need to set UUCPNAME to their official UUCP name.

They will also probably set RELAY_MAILER and RELAY_HOST which enable smart-host routing through a mail relay.

The mail transport to be used is defined in RELAY_MAILER and should usually be UUCP-A for UUCP sites. If your site is SMTP-only and talks `Domain Name Service', you would change the RELAY_MAILER.

If you're a SLIP site, you might want to take the easy way out and just forward all outgoing mail to your service provider to do the right thing with. To do so, you'd want to define ISOLATED_DOMAINS and VALIDATION_DOMAINS to be your domain, you'd also want to define RELAY_HOST to be your service provider and RELAY_MAILER to be TCP. Of course, you want to ask permission before you set any system up as your general purpose relay.

6.4 Sendmail 8.x

Sendmail 8.7.x from Berkeley was the latest major revision after sendmail5. It had wonderful built-in support for building under Linux : just "make linux" and all was set.

You'll probably be best served by grabbing one of the various binary distributions off of the usual Linux archive sites rather than fighting things like Berkeley dbm yourself.

There's a nice distribution of sendmail 8.6.12 from Jason Haar - j.haar at lazerjem.demon.co.uk on sunsite.unc.edu in /pub/Linux/system/Mail/delivery/sendmail-8.6.12-bin.tgz that has the source documentation and a very nice quickie description of how to run sendmail v8 for common configurations.

The bottom line with sendmail v8 is that you want to configure the bare minimum necessary to get the job done ; the following is an example that should get you close at least.

A sample 8.7.x mc file

Much like sendmail+IDA, sendmail v8 uses m4 to process a config file into a full sendmail.cf that sendmail uses. The following is my current mc file for my site (ppp to Internet for outgoing mail, uucp for incoming mail).

        dnl divert(-1)
        #---------------------------------------------------------------------
        #
        # this is the .mc file for a linux host that's set up as follows:
        #
        #       - connected to Internet for outbound mail (ppp here)
        #       - connected via UUCP for incoming mail
        #       - domainized headers
        #       - no local mailer (use 'deliver' instead)
        #       - no DNS running so don't canonicalize outgoing via DNS
        #       - all non-local outbound mail goes to the RELAY_HOST over smtp
        #           (we run ppp and let our service provider do the work)
        #
        #                                       vds 3/31/95
        #
        #---------------------------------------------------------------------
        include(`../m4/cf.m4')
        VERSIONID(`linux nodns relays to slip service provider smarthost')dnl
        Cwmyhostname.myprimary.domain myhostname.UUCP localhost
        OSTYPE(linux)
        FEATURE(nodns)dnl
        FEATURE(always_add_domain)dnl
        FEATURE(redirect)
        FEATURE(nocanonify)
        dnl MAILER(local)dnl
        MAILER(smtp)dnl
        MAILER(uucp)dnl
        define(`RELAY_HOST', smtp:my.relay.host.domain)
        define(`SMART_HOST', smtp:my.relay.host.domain)
        define(`UUCP_RELAY', smtp:my.relay.host.domain)
        define(`LOCAL_MAILER_PATH', `/bin/deliver')
        define(`LOCAL_MAILER_ARGS', `deliver $u')

Sendmail v8 tidbits

There are a few differences I suppose to the 'IDA bigots' among us. So far, I've found the following:

Instead of 'runq', you type 'sendmail -q' to run the queue!

6.5 Local Delivery Agents

Unlike most operating systems, Linux did not have mail "built-in": you needed a program to deliver the local mail, like "lmail", "procmail" or "deliver".

However, every recent distribution includes a local mailer now!

Documentation for how to use either for local delivery is in the sendmail5.67b+IDA1.5 binary release (on sunsite) mentioned above.


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