---------------------- Frequently Asked Questions ----------------------------
1. How do I go about setting up a mailinglist or a mail-archive server?
Look in the SmartList directory, start reading the INTRO file,
it describes it in detail and should get you started.
2. I installed procmail (i.e. typed 'make install'), but how am I supposed to
use it? When I type procmail on the command line it simply does nothing.
There exists an excellent newbie FAQ about mailfilters (and procmail
in particular), it is being maintained by Nancy McGough <email@example.com>
and can be obtained via:
World Wide Web (the nicest format for online reading!):
Send mail to firstname.lastname@example.org containing the following:
It is also posted monthly in at least the following newsgroups:
comp.mail.misc, comp.answers, news.answers
You're not supposed to start procmail from the command line.
Procmail expects exactly one mail message to be presented to it
on its stdin. Usually the mail system feeds it into procmail.
If you start it by hand, you have to type the mail.
Be sure to have a .forward and a .procmailrc file in your home
directory (see the examples subdirectory or the man page).
MMDF users should note that they need a .maildelivery file *instead*
of a .forward file (see the man page for more detailed information).
If however, procmail has been integrated in the maildelivery system
(i.e. if your system administrator installed it that way, ask him/her),
then you no longer need the .forward files in your home directory,
having a .procmailrc file will suffice.
On some systems .forward files are not checked.
It might be possible that your system supports a command like:
mail -F "|/usr/bin/procmail"
to set up forwarding to a program. (If procmail is in /usr/local/bin
then use that path instead when trying these.)
If that doesn't seem to work it might be worth trying to put a line
looking like this:
Forward to |/usr/bin/procmail
or if that doesn't work, try:
Pipe to /usr/bin/procmail
as the only line in your mail spool file (e.g. /var/mail/$LOGNAME), as
well as doing a "chmod 06660 /var/mail/$LOGNAME". For more information
on such systems, do a "man mail".
If all of this doesn't work, procmail can be called on a periodical
basis, either via "cron", "at" or whenever you start reading mail (or
log in). For a sample script look in the NOTES section of the
procmail(1) man page.
3. When I compile everything the compiler complains about invalid or illegal
pointer combinations, but it produces the executables anyway.
Should I be concerned?
Ignore these warnings, they simply indicate that either your compiler
or your system include files are not ANSI/POSIX compliant.
The compiler will produce correct code regardless of these warnings.
4. The compiler seems to issue warnings about "loop not entered at top",
is that a problem?
No, no problem at all, it just means I wrote the code :-).
That's just about the only uncommon coding technique I use (don't
think I don't try to avoid those jumps in loops, it's just that
sometimes they are the best way to code it). This warning, as
well as "statement not reached", can be ignored -- the compiler
will still generate correct code. Use gcc if they really bother
5. The compiler complains about unmodifiable lvalues or assignments to const
variables. Now what?
Well, if the compiler produces the executables anyway everything
probably is all right. If it doesn't, you might try inserting a
"#define const" in the autoconf.h file by hand. However in any case,
your compiler is broken; I would recommend submitting this as a
compiler bug to your vendor. In any case, if this should occur, I'd
appreciate a mail from you (so I can try to fix the autoconf script
to recognise your compiler correctly as well).
6. The compiler refuses to compile regexp.c, what is the problem?
Try compiling that module with optimisation turned off.
7. Everything installed just fine, it's just that there are several stale
_locktst processes which refuse to die. How do I get rid of those?
In order to prevent things like this from happening to procmail,
_locktst tries to determine which kernel locking methods are
reliable. Sometimes this triggers a bug in the kernel or in
your system-supplied lockd; this is good, because _locktst detects
this and makes sure that procmail will not make the same mistake.
A side effect is that this sometimes leaves behind some stale
_locktst processes that seem to be unkillable.
This usually is the result of a buggy lockdaemon. In order to
get rid of the stale processes, ask your system administrator
to kill and restart the (rpc.)lockd (and perhaps the (rpc.)statd)
on both the filesystem-client (where you compiled procmail) and the
filesystem-server(s) (where the lockingtests took place).
Depending on the OS it might help if you send the offending
_locktst processes a kill signal before or after restarting the
In any case, _locktst just uncovered a bug in your operating system.
You should contact your system's vendor and ask for a bugfix for
8. When I send myself a testmail, the mail bounces with the message: cannot
execute binary file. What am I doing wrong?
It is very well possible that mail is processed on a different
machine from that where you usually read your mail. Therefore you
have to make sure that procmail has the right binary format to
execute on those machines on which mail could arrive. In order to
get this right you might need to do some .forward file tweaking,
look at the examples/advanced file for some suggestions.
9. Where do I look for examples about:
One home directory, several machine architectures?
Procmail as an integrated local mail delivery agent? (generic,
sendmail, ZMailer, smail, SysV mailsurr)
Changing the mail spool directory to $HOME for all users
Security considerations (when installing procmail suid root)
Well, this probably is your lucky day :-), all these topics are covered
in the examples/advanced file.
Other examples (e.g. for autoreplies) are most likely to be found by
typing: man procmailex
10. How do I use procmail as a general mail filter inside sendmail?
See EXAMPLES section of the procmail(1) man page.
11. Why do I have to insert my login name after the '#' in the .forward or
Some mailers `optimise' maildelivery and take out duplicates from
Cc:, Bcc: and alias lists before delivery. If two or more persons on
such a list would have identical .forward files, then the mailer will
eliminate all but one. Adding a `#' with your login name following
it will make the .forward files unique, and will ensure that the mailer
doesn't optimise away some addresses.
12. How do I view the man pages?
If the man(1) program on your system understands the MANPATH
environment variable, make sure that the installation directory listed
in the Makefile for the manpages is included in your MANPATH. If your
man program does not support MANPATH, make sure that the man pages
are installed in one of the standard man directories, like under
/usr/man. If you do not want to install the man pages before viewing
them, you can view an individual man file by typing something like:
nroff -man procmail.1 | more
13. The leading From_ line on all my arriving mail shows the wrong time.
Before putting procmail in the .forward file everything was OK.
This is a known bug in sendmail-5.65c+IDA. The real fix would be
to upgrade to sendmail 6.x or later. For a quick fix, see the
procmailex man page.
14. When sending mail to someone with procmail in his/her .forward I sometimes
get back an error saying: "Cannot mail directly to programs."
This is a known bug in some older sendmails that mistakenly drop
their root privileges when they are given the -t flag. Either
make sure that your sendmail always forwards to a mailserver first or
upgrade to sendmail 6.x or later.
15. When sending mail to someone with procmail in his/her .forward I sometimes
get back an error saying:
"User doesn't have a valid shell for mailing to programs."
This indicates that the mail arrives on a mailserver which most likely
has a different user database (/etc/passwd) where the login shell
specified for the recipient is not present in /etc/shells.
Contact your administrator to put the name of that shell in
16. My mailtool sometimes reports that it is confused about the state of
the mailbox, or I get "Couldn't unlock" errors from procmail now and then,
or sometimes it simply seems to hang just when new mail arrives.
This is a known bug in the OpenLook mailtool. It holds on to
the kernel lock on the mail-spoolfile most of the time as a
signal to other mailtool processes. With newer versions of
mailtool, enabling the "Use network aware mail file locking"
configuration option may solve the problem, though this option
isn't always available. If that doesn't work then recompile
procmail with both the fcntl() and lockf() locking method
disabled (see config.h).
17. I sometimes get these `Lock failure on "/var/mail/$LOGNAME.lock"' errors
from procmail. What do I do about it?
The problem here is that as long as procmail has not read a
$HOME/.procmailrc file, it can hang on to the sgid mail permission
(which it needs in order to create a lockfile in /var/mail).
I.e. if procmail delivers mail to a user without a $HOME/.procmailrc
file, procmail *can* (and does) use the /var/mail/$LOGNAME.lock file.
If, however, it finds a $HOME/.procmailrc file, procmail has to let go
of the sgid mail permission because otherwise any ordinary user could
There are several solutions to this problem:
- Some systems support the sticky bit on directories (when set only
allows the owner of a file in that directory to rename or remove
it). This enables you to make /var/mail drwxrwxrwt. It is
thus effectively world writable, but all the mailboxes in it are
protected because only the mailbox owner can remove or rename it.
- If your system did not exhibit the !@#$%^&* POSIX semantics for
setgid(), procmail would have been able to switch back and forth
between group mail and the group the recipient belongs to without
creating security holes.
- If your system supported setrgid() or setregid() or setresgid()
with BSD semantics, procmail would have been able to switch...
(see the previous point).
- You could simply put the following at the end of your .procmailrc
LOCKFILE # removes any preexisting lockfile
TRAP="rm -f $DEFAULT$LOCKEXT"
- You could, instead of using /var/mail/$LOGNAME, use a file below
your home directory as your default mailbox.
- Or, you could still use /var/mail/$LOGNAME as the mailbox, but
simply instruct procmail to use a different lockfile. This can
be achieved by putting following recipe at the bottom of
your .procmailrc file:
You have to make sure that all other programs that update your
system mailbox will be using the same lockfile of course.
- You can ignore the problem if you know that both your mail reader
and procmail use an overlapping kernel locking method.
18. Is procmail Y2K safe/compliant?
Both procmail and formail are believed to be Y2K compliant if
your system's libraries are Y2K compliant. In particular, they
use the time_t type to hold the current time when it is needed
and print out the time using the ctime() library routine.
However, no actual compliancy tests have been run, so you if
you need that you'll need to run them yourself.
For those who have examined the code themselves, the casting of
a time_t value to unsigned long in formail.c is guaranteed to
work according to the current version of the C language
standard. Future revisions of that standard may change that,
at which time formail will be updated to work with both the new
and the old standards.
Individual recipes and rcfiles may need to be checked for
unsafe date handling.
19. How can I make procmail deliver a message to all local users? E-mail
for several people all come into a single mailbox and I'm trying to
split them back up.
If you are asking this, you are on the wrong track. Procmail
cannot route messages like this correctly without special help
from the MTA (sendmail, qmail, etc). For a more lengthy
discussion about the issues, please refer to
20. None of the above topics cover my problem. Should I panic?
Let me ask you a question :-), have you examined the CAVEATS,
WARNINGS, BUGS and NOTES sections of the manual pages *closely* ?
Have you checked any of the FAQs referenced from the procmail
website, http://www.procmail.org, to see if the answer it? If
you have, well, then panic. Or, alternatively, you could
submit your question to the procmail mailinglist (see the man
page for the exact addresses, or try "procmail -v", or look in
the patchlevel.h file).