Sendmail Installation and Operation Guide
SMM:08-11
1.3.7. /var/spool/mqueue
The directory /var/spool/mqueue should be created to hold the mail queue. This directory
should be mode 0700 and owned by root.
The actual path of this directory is defined by the QueueDirectory option of the send-
mail.cf file. To use multiple queues, supply a value ending with an asterisk. For example,
/var/spool/mqueue/qd* will use all of the directories or symbolic links to directories beginning
with `qd' in /var/spool/mqueue as queue directories. Do not change the queue directory struc-
ture while sendmail is running.
If these directories have subdirectories or symbolic links to directories named `qf', `df',
and `xf', then these will be used for the different queue file types. That is, the data files are
stored in the `df' subdirectory, the transcript files are stored in the `xf' subdirectory, and all oth-
ers are stored in the `qf' subdirectory.
If shared memory support is compiled in, sendmail stores the available diskspace in a
shared memory segment to make the values readily available to all children without incurring
system overhead. In this case, only the daemon updates the data; i.e., the sendmail daemon cre-
ates the shared memory segment and deletes it if it is terminated. To use this, sendmail must
have been compiled with support for shared memory (-DSM_CONF_SHM) and the option
SharedMemoryKey
must be set. Notice: do not use the same key for sendmail invocations
with different queue directories or different queue group declarations. Access to shared memory
is not controlled by locks, i.e., there is a race condition when data in the shared memory is
updated. However, since operation of sendmail does not rely on the data in the shared memory,
this does not negatively influence the behavior.
1.3.8. /var/spool/clientmqueue
The directory /var/spool/clientmqueue should be created to hold the mail queue. This
directory should be mode 0770 and owned by user smmsp, group smmsp.
The actual path of this directory is defined by the QueueDirectory option of the submit.cf
file.
1.3.9. /var/spool/mqueue/.hoststat
This is a typical value for the HostStatusDirectory option, containing one file per host
that this sendmail has chatted with recently. It is normally a subdirectory of mqueue.
1.3.10. /etc/mail/aliases*
The system aliases are held in "/etc/mail/aliases". A sample is given in "sendmail/aliases"
which includes some aliases which must be defined:
cp sendmail/aliases /etc/mail/aliases
edit /etc/mail/aliases
You should extend this file with any aliases that are apropos to your system.
Normally sendmail looks at a database version of the files, stored either in
"/etc/mail/aliases.dir" and "/etc/mail/aliases.pag" or "/etc/mail/aliases.db" depending on which
database package you are using. The actual path of this file is defined in the AliasFile option of
the sendmail.cf file.
The permissions of the alias file and the database versions should be 0640 to prevent local
denial of service attacks as explained in the top level README in the sendmail distribution. If
the permissions 0640 are used, be sure that only trusted users belong to the group assigned to
those files. Otherwise, files should not even be group readable.