Ubuntu Manpage: tmail - Mail Delivery Module

Provided by: uw-mailutils_2007f~dfsg-2_amd64

NAME

       tmail - Mail Delivery Module

SYNOPSIS

       tmail [-b format] [-D] [-f from_name] [-I inbox_specifier] user[+folder] ...

DESCRIPTION

tmail delivers mail to a user's INBOX or a designated folder. tmail may be configured as a drop-in
replacement for binmail(1), mail.local(1) or any program intended for use for mail delivery by a mail
delivery program such as sendmail(8).

tmail is intended to be used for direct delivery by the mailer daemon; dmail(1) is the preferred tool for
user applications, e.g. a mail delivery filter such as procmail(1). If tmail is used for a user
application, then the calling program must be aware of the restrictions noted below.

When tmail exits, it returns exit status values to enable the mail delivery program to determine whether
a message was delivered successfully or had a temporary (requeue for later delivery) or permanent (return
to sender) failure.

If the +folder extension is included in the user argument, tmail will attempt to deliver to the
designated folder. If the folder does not exist or the extension is not included, the message is
delivered to the user's INBOX. If delivery is to INBOX and no INBOX currently exists, tmail will create
a new INBOX, using the -I or -b flag if specified. tmail recognizes the format of an existing INBOX or
folder, and appends the new message in that format.

The -b flag specifies a format to create INBOX if INBOX does not already exist. This flag requires
privileges, and can not be used with -I. The argument is a format name such as mix, mbx, etc.

The -D flag specifies debugging; this enables additional message telemetry.

The -f or -r flag is used by the mail delivery program to specify a Return-Path. The header
Return-Path: <from_name>
is prepended to the message before delivery.

The -I flag is used by the mail delivery program to specify an alternative INBOX name. This flag
requires privileges, and can not be used with -b. This affects the location and format of INBOX. If
specified, it should be in one of three forms:

The first form of argument to -I is the string "INBOX", which means to write to the system default inbox
using the system default mailbox format. These system defaults are defined when the c-client library is
built.

The second form of argument to -I is a delivery specification, consisting of "#driver.", a c-client
mailbox format driver name, "/", and a file name. This will write to the specified file in the specified
format. For example, #driver.mbx/INBOX will write to file "INBOX" in the home directory in mbx format;
and #driver.unix/mail/incoming will write to file "incoming" in the user's "mail" subdirectory in unix
(default UNIX) format.

The third form of argument to -I is any other name. Normally, this will write to the specified file on
the user's home directory in the specified format. However, certain names are special. These are:

value equivalant to
----- -------------
INBOX.MTX #driver.mtx/INBOX.MTX
mbox #driver.unix/mbox
mail.txt #driver.tenex/mail.txt

If -I is not specified, the default action is -I INBOX.

If multiple recipients are specified on the command line, tmail spawns one child process per recipient to
perform actual delivery. This way of calling tmail is not recommended; see below under RESTRICTIONS.

INSTALLATION

       If tmail is to be used for mail delivery from the mail delivery program,  it  must  be  installed  setuid
       root.

       If sendmail is the mail delivery program, tmail is invoked from sendmail.cf.  Look for the "Mlocal" line,
       and substitute the path name for the tmail binary in place of /bin/mail, /usr/lib/mail.local,  etc.   You
       should  also  add  the flag to invoke tmail with CRLF style newlines; this is usually done with E=\r\n in
       the Mlocal line.

       Here is an example of an Mlocal line in sendmail version 8:

       Mlocal, P=/usr/local/etc/tmail, F=lsDFMAw5:/|@qPrn+,
         S=10/30, R=20/40, E=\r\n, T=DNS/RFC822/X-Unix,
         A=tmail $u

       If tmail is to be called with the -I flag, it must be invoked with both  real  and  effective  UID  root.
       Many  sendmail  configurations invoke the local mailer as the sending user when that user is local, which
       will prevent -b or -I from working.

SECURITY CONSIDERATIONS

       If tmail is invoked by an ordinary user, the Received: header line will indicate the name or UID  of  the
       user that invoked it.

       Ordinary users are not permitted to use the -b or -I flag since otherwise a user could create any file on
       another user's directory.

       tmail can deliver mail to home directories.  In addition, tmail can be used to deliver mail to other mail
       folders in a home directory or an inferior directory of a home directory.

RESTRICTIONS

       The calling program should invoke tmail with CRLF newlines, otherwise tmail will complain in syslog.

       Absolute pathnames and ~user specifications are not permitted in +folder extensions.

       Ordinary users are not permitted to use the -I flag.

       IMAP4 namespace names are not yet supported in +folder extensions.

       It is not possible to use tmail to deliver to mh(1) format mailboxes.

       If  delivery  to  multiple  users is specified and delivery to any single user fails, the entire delivery
       will be reported as having failed, even though delivery to other users may have succeeded.  If  tmail  is
       used  for  mail  delivery  from  sendmail(8),  a  separate tmail invocation should be done for each user.
       Otherwise a delivery failure for a single user in a message going to multiple users will  cause  multiple
       deliveries to all the other users every time sendmail(8), retries.

AUTHOR

       Mark Crispin, MRC@CAC.Washington.EDU