FreeBSD configuration File

/etc/login.conf

/etc/login.conf describes user parameters set at login time.

In UNIX tradition, root has been the owner of the universe. This is rather primitive, and the 4.3BSD Net/2 relase introduced login classes, which determine session accounting, resource limits and user environment settings. Many programs use the database described in /etc/login.conf to set up a user's login environment and to enforce policy, accounting and administrative restrictions. The login class database also provides the means to authenticate users to the system and to choose the type of authentication.

When creating a user, you may optionally enter a class name, which should match an entry in /etc/login.conf—see page 146 for more details. If you don't, the system uses the entry default for a non-root user. For the root user, the system uses the entry root if it is present, and default otherwise.

The structure of the login configuration database is relatively extensive. It describes a number of parameters, many of which can have two values: a current value and a maximum value. On login, the system sets the values to the -cur (current) value, but the user may, a this option, increase the value to the -max (maximum) value. We'll look at the default entry for an example.

default:\
    :passwd_format=md5:\
    :copyright=/etc/COPYRIGHT:\
    :welcome=/etc/motd:\
    :setenv=MAIL=/var/mail/$,BDOCKSIZE=K,FTP_PASSIVE_MODE=YES:\
    :path=/sbin /bin /usr/sbin /usr/bin /usr/games /usr/local/sbin /usr/local/bi
n/usr/X11R6/bin ~/bin:\
    :nologin=/var/run/nologin:\
    :cputime=unlimited:\
    :datasize=unlimited:\
    :stacksize=unlimited:\
    :memorylocked=unlimited:\
    :memoryuse=unlimited:\
    :filesize=unlimited:\
    :coredumpsize=unlimited:\
    :openfiles=unlimited:\
    :maxproc=unlimited:\
    :sbsize=unlimited:\
    :vmemoryuse=unlimited:\
    :priority=0:\
    :ignoretime@:\
    :umask=022:

As in the password file, the fields are delimited by colons (:). In this example, though, lines are continued by placing a backslash (\) at the end of each line except the last. This usage is common in UNIX. Unlike Microsoft usage, a backslash is never used to represent a directory.

This entry defines the following parameters:

• passwd_format controls the password format used for new passwords. It takes the values des, md5 or blf. See the login.conf(5) manual page for more information about login capabilities.
• Processes may use as much CPU time as they want. If you change this, you can stop processes that use more than a specific amount of CPU time.
• The current maximum sizes of the user data segment and the stack are set to 64 MB. The entry doesn't define maximum values for these parameters.
• The user may lock a maximum of 10 MB of memory per process.
• The total memory use per process may not exceed 100 MB.
• There is no limit on the size of data files or core dump files that the user may create.
• The user may have upto 64 processes.
• Each process may have upto 64 open files. For some programs, this could be a limitation.
• The user need not have a home directory to login. The @ symbol specifies that the preceding symbol (requirehome) should be undefined. As a result, the system does not require the home directory.
• By default, the umask is set to 022. See page 184 for more details of umask.
• The system uses the default authentication scheme for this user.

See the man page login.conf(5) for further details.

/etc/motd

/etc/motd (message ofthe day ) is a file whose contents are printed out at login. You can put any message you like in it. See page 114 for an example.

/etc/newsyslog.conf

/etc/newsyslog.conf contains configuration information for the newsyslog command: which log files to archive, how many copies, and whether to compress. See newsyslog(8) for further details. If you generate a lot of logging information, you may need to modify this file to avoid overflowing the file system with your/var/log directory.

/etc/nsswitch.conf

/etc/nsswitch.conf tells the resolver how to perform name resolution. This file format comes from Solaris and replaces the older /etc/host.conf. It gives you the flexibility to use both /etc/hosts and DNS lookups, for example. You specify the lookup sequence for hostnames with a line like this:

hosts:    files dns

The word hosts here specifies the type of lookup (for host names, not NIS, password entries or something else). The keyword file represents the /etc/hosts file in this case. This file is not installed by default; see the man page nsswitch.conf(8) if you need to use it.

/etc/pccardd.conf

/etc/pccardd.conf and its companion /etc/defaults/pccardd.conf are the configuration files for pccardd. We looked at them in detail in "Chapter 17" , on page 304.

/etc/periodic.conf

/etc/periodic.conf controls how to perform the maintenance jobs that cron runs during the night:

# Perform  daily/weekly/monthly maintenance.
1       3            *      *      *    root    periodic daily
15      4            *      *      6    root    periodic weekly
30      5            1      *      *    root    periodic monthly

Like /etc/rc.conf, /etc/periodic.conf is an optional file which overrides the default file /etc/defaults/periodic.conf. You don't need to change it at all, but you may find it worthwhile. Read the man page periodic.conf(5) or the file /etc/defaults/periodic.conf for more details.

/etc/printcap

/etc/printcap describes the printers connected to a system. See page 265 for more details.

/etc/profile

/etc/profi le is a default startup file for Bourne-style shells. See page 130 for more details.

/etc/rc.firewall

/etc/rc.firewall is used to initialize the packet filtering firewall ipfw. See page 389 for further details.

/etc/resolv.conf

/etc/resolv.conf is used by the resolver library to locate name servers to perform DNS lookups. See 366 for more details.

/etc/syslog.conf

/etc/syslog.conf is the configuration file for syslogd. See syslogd.conf(5) for further details.