%general-entities; ]> Shadow If you would like to enforce the use of strong passwords, refer to for installing Cracklib prior to building Shadow. After Cracklib is installed, execute this sed in Shadow's source directory to correct the path to the Cracklib dictionary: sed -i 's@\(DICTPATH.\).*@\1/lib/cracklib/pw_dict@' etc/login.defs Finally, add --with-libcrack to the configure command below. Disable the installation of the groups program and man pages, as better versions of these programs are provided by Coreutils, Util-linux and Man-pages: sed -i src/Makefile.in \ -e 's/groups$(EXEEXT) //' find man -name Makefile.in -exec sed -i \ -e 's/man1\/groups\.1 //' \ -e 's/man3\/getspnam\.3 //' \ -e 's/man5\/passwd\.5 //' '{}' \; Prepare Shadow for compilation: ./configure \ --sysconfdir=/etc \ --with-group-max-length=32 --sysconfdir=/etc Tells Shadow to install its configuration files into /etc, rather than /usr/etc. --with-group-max-length=32 The maximum user name is 32 characters. Make the maximum group name the same. Compile the package: make This package does not come with a test suite. Install the package: make install Instead of using the default DES method, use the more secure SHA512 method of password encryption, which also allows passwords longer than 8 characters. It is also necessary to change the obsolete /var/spool/mail location for user mailboxes that Shadow uses by default to the /var/mail location used currently. Use the following sed command to make these changes to the appropriate configuration file: /etc/login.defs sed -i /etc/login.defs \ -e 's@#\(ENCRYPT_METHOD \).*@\1SHA512@' \ -e 's@/var/spool/mail@/var/mail@' Move a misplaced program to its proper location: mv -v /usr/bin/passwd /bin The login program will write to /var/log/faillog, to record failed login attempts, and /var/log/lastlog, to record the date and time of the latest successful login for each user. These log files are not created automatically if they do not already exist, so we will create them now and give them appropriate ownership and permissions: touch /var/log/{fail,last}log chgrp -v utmp /var/log/{fail,last}log chmod -v 664 /var/log/{fail,last}log Shadow configuring This package contains utilities to add, modify, and delete users and groups; set and change their passwords; and perform other administrative tasks. For a full explanation of what password shadowing means, see the doc/HOWTO file within the unpacked source tree. If using Shadow support, keep in mind that programs which need to verify passwords (display managers, FTP programs, pop3 daemons, etc.) must be Shadow-compliant. That is, they need to be able to work with shadowed passwords. To enable shadowed passwords, run the following command: pwconv To enable shadowed group passwords, run: grpconv To view or change the default settings for new user accounts that you create, you can edit /etc/default/useradd. See man useradd or for more information. Choose a password for user root and set it by running: passwd root Installed programs Installed directory chage, chfn, chgpasswd, chpasswd, chsh, expiry, faillog, gpasswd, groupadd, groupdel, groupmems, groupmod, grpck, grpconv, grpunconv, lastlog, login, logoutd, newgrp, newusers, nologin, passwd, pwck, pwconv, pwunconv, sg (link to newgrp), su, useradd, userdel, usermod, vigr (link to vipw), vipw /etc/default Short Descriptions chage Used to change the maximum number of days between obligatory password changes chage chfn Used to change a user's full name and other information chfn chgpasswd Used to update group passwords in batch mode chgpasswd chpasswd Used to update the passwords of an entire series of user accounts chpasswd chsh Used to change a user's default login shell chsh expiry Checks and enforces the current password expiration policy expiry faillog Is used to examine the log of login failures, to set a maximum number of failures before an account is blocked, or to reset the failure count faillog gpasswd Is used to add and delete members and administrators to groups gpasswd groupadd Creates a group with the given name groupadd groupdel Deletes the group with the given name groupdel groupmems Allows a user to administer his/her own group membership list without the requirement of superuser privileges groupmems groupmod Is used to modify the given group's name or GID groupmod grpck Verifies the integrity of the group files /etc/group and /etc/gshadow grpck grpconv Creates or updates the shadow group file from the normal group file grpconv grpunconv Updates /etc/group from /etc/gshadow and then deletes the latter grpunconv lastlog Reports the most recent login of all users or of a given user lastlog login Is used by the system to let users sign on login logoutd Is a daemon used to enforce restrictions on log-on time and ports logoutd newgrp Is used to change the current GID during a login session newgrp newusers Is used to create or update an entire series of user accounts newusers nologin Displays a message that an account is not available. It is designed to be used as the default shell for disabled accounts. nologin passwd Is used to change the password for a user or group account passwd pwck Verifies the integrity of the password files /etc/passwd and /etc/shadow pwck pwconv Creates or updates the shadow password file from the normal password file pwconv pwunconv Updates /etc/passwd from /etc/shadow and then deletes the latter pwunconv sg Executes a given command while the user's GID is set to that of the given group sg su Runs a shell with substitute user and group IDs su useradd Creates a new user with the given name, or updates the default new-user information useradd userdel Deletes the given user account userdel usermod Is used to modify the given user's login name, User Identification (UID), shell, initial group, home directory, etc. usermod vigr Edits the /etc/group or /etc/gshadow files vigr vipw Edits the /etc/passwd or /etc/shadow files vipw