Like any other piece of software (and information generally), qmail
comes with NO WARRANTY.

Configuration: The qmail home directory is /var/qmail. (This must be a
local directory, not shared among machines. Under Linux, make sure that
all mail-handling filesystems are mounted with synchronous metadata.)
The user-ext delimiter is -. The silent concurrency limit is 120. The
queue subdirectory split is 23.

To set up qmail to receive and deliver mail, start at step 9 of
/var/qmail/doc/INSTALL.  

Added by the packager:

I have made a good-faith attempt to ensure that the package behaves
correctly, and I believe this package meets the requirements set forth in 
ftp://koobera.math.uic.edu/www/qmail/dist.html.  The only changes I made are:

1) The package installs only the unformatted man pages.  There are no
man/cat? directories under RedHat, and creating them creates havoc. To
make install and instcheck work for this change, I made the following
change to hier.c:

grep -v "man/cat*" hier.c > hier.c.tmp 
mv hier.c.tmp hier.c

2) The package does not contain the fastforward and dot-forward packages. 

3) I think you want to execute the minimal surviving command of step 5
of /var/qmail/doc/INSTALL before you start with step 9.

Compilation environment:

Compiler: gcc version 2.96 20000731 (Red Hat Linux 7.3 2.96-110)  
Hardware: i686 
Library: glibc-2.2.5-34
OSversion: Linux 2.4.18-4 
Packager: mw@csi.hu
RedHat release: Red Hat Linux release 7.3 (Valhalla)
rpm version: rpm-4.0.4-7x.18