make - create /etc/courier/userdb
vchkpw2userdb [ --vpopmailhome=dir ] [ --todir=dir ]
makeuserdb creates /etc/courier/userdb.dat from the contents of
/etc/courier/userdb. /etc/courier/userdb's contents are described
later in this document. Maildrop, Courier, and other applications use
/etc/courier/userdb.dat as a substitute/complement for your system
password file. The usual purpose for /etc/courier/userdb.dat is to
specify "virtual" accounts - accounts that do not have an associated
system login. Usually (but not necessarily) all virtual accounts share
the same system userid. /etc/courier/userdb.dat may also replace your
system password file. Because the system password file is a text file,
when there's a large number of accounts it will be significantly faster
to search @userdb.dat@, which is a binary database, instead of a flat
text file that the system password file usually is.
The makeuserdb command can be safely executed during normal system
FORMAT OF /ETC/COURIER/USERDB
/etc/courier/userdb is a plain text file that can be created using any
text editor. Blank lines are ignored. Lines that start with the # char-
acter are comments, and are also ignored. Other lines define proper-
ties of a single "account", one line per account. /etc/courier/userdb
may be a directory instead of a plain file. In that case all files in
/etc/courier/userdb are essentially concatenated, and are treated as a
single file. Each line takes the following format:
name is the account name. name MUST contain only lowercase characters
If Courier is configured to treat lowercase and uppercase account names
as identical, name is followed by exactly one tab character, then a
list of field/value pairs separated by vertical slashes. field is the
name of the field, value is the field value. Fields and values them-
self cannot contain slashes or control characters. Fields may be spec-
ified in any order. Here are all the currently defined fields. Note
that not every field is used by every application that reads
uid - value is a (possibly) unique numerical user ID for this
gid - value is a (possibly) unique numerical group ID for this
home - value is the account's home directory.
shell - value is the account's default login shell.
systempw - value is the account's password. See userdbpw(8) for
details on how to set up this field.
pop3pw, esmtppw, imappw... - value specifies a separate password
used only for authenticating access using a specific service,
such as POP3, IMAP, or anything else. If not defined, systempw
is always used. This allows access to an account to be
restricted only to certain services, such as POP3, even if other
services are also enabled on the server.
mail - value specifies the location of the account's Maildir
mailbox. This is an optional field that is normally used when
userdb is used to provide aliases for other mail accounts. For
example, one particular multi-domain E-mail service configura-
tion that's used by both Qmail and Courier servers is to deliver
mail for a mailbox in a virtual domain, such as "user@exam-
ple.com", to a local mailbox called "example-user". Instead of
requiring the E-mail account holder to log in as "example-user"
to download mail from this account, a userdb entry for
"userATexample.com" is set up with mail set to the location of
example-user's Maildir mailbox, thus hiding the internal mail
configuration from the E-mail account holder's view.
quota - value specifies the maildir quota for the account's
Maildir. This has nothing to do with actual filesystem quotas.
Courier has a software-based Maildir quota enforcement mechanism
which requires additional setup and configuration. See
maildirquota(7) for additional information.
All fields whose name ends with 'pw' will NOT copied to
/etc/courier/userdb.dat. These fields will be copied to
/etc/courier/userdbshadow.dat. makeuserdb creates /etc/courier/userdb-
shadow.dat without any group and world permissions. Note that
makeuserdb reports an error if /etc/courier/userdb has any group or
CONVERTING /ETC/PASSWD AND VPOPMAIL TO /ETC/COURIER/USERDB FORMAT
pw2userdb reads the /etc/passwd and /etc/shadow files and converts all
entries to the /etc/courier/userdb format, printing the result on stan-
dard output. The output of pw2userdb can be saved as
/etc/courier/userdb (or as some file in this subdirectory). Linear
searches of /etc/passwd can be very slow when you have tens of thou-
sands of accounts. Programs like maildrop always look in
/etc/courier/userdb first. By saving the system password file in
/etc/courier/userdb it is possible to significantly reduce the amount
of time it takes to look up this information.
After saving the output of pw2userdb, you must still run makeuserdb to
vchkpw2userdb converts a vpopmail-style directory hierarchy to the
/etc/courier/userdb format. This is an external virtual domain manage-
ment package that's often used with Qmail servers.
Generally, an account named 'vpopmail' is reserved for this purpose.
In that account the file users/vpasswd has the same layout as
/etc/passwd, and performs a similar function, except that all userid in
users/vpasswd have the same userid. Additionally, the domains subdi-
rectory stores virtual accounts for multiple domains. For example,
domains/example.com/vpasswd has the passwd file for the domain exam-
ple.com. Some systems also have a soft link, domains/default, that
points to a domain that's considered a "default" domain.
The vchkpw2userdb reads all this information, and tries to convert it
into the /etc/courier/userdb format. The --vpopmailhost option speci-
fies the top level directory, if it is not the home directory of the
The vchkpw2userdb script prints the results on standard output. If
specified, the --todir option tries to convert all vpasswd files one at
a time, saving each one individually in dir. For example:
It is still necessary to run makeuserdb, of course, to create the
binary database file /etc/courier/userdb.dat
NOTE: You are still required to create the /etc/courier/userdb entry
which maps system userids back to accounts, "uid=<TAB>name", if that's
applicable. vchkpw2userdb will not do it for you.
NOTE: makeuserdb may complain about duplicate entries, if your
"default" entries in users/vpasswd or domains/default/vpasswd are the
same as anything in any other /etc/courier/userdb file. It is also
likely that you'll end up with duplicate, but distinct, entries for
every account in the default domain. For example, if your default
domain is example.com, you'll end up with duplicate entries - you'll
have entries for both user and email@example.com.
If you intend to maintain the master set of accounts using vchkpw/vpop-
mail, in order to avoid cleaning this up every time, you might want to
consider doing the following: run vchkpw2userdb once, using the --todir
option. Then, go into the resulting directory, and replace one of the
redundant files with a soft link to /dev/null. This allows you to run
vchkpw2userdb without having to go in and cleaning up again, after-
/etc/courier/userdb.tmp - temporary file
/etc/courier/userdbshadow.tmp - temporary file
makeuserdb is a Perl script, and uses Perl's portable locking. Perl's
documentation notes that certain combinations of locking options may
not work with some networks.
userdb(8), maildrop(8), courier(8), maildirquota(7).
Double Precision, Inc. 27 August 2004 MAKEUSERDB(8)