PAM_PWHISTORY(8)

  .SH "NAME" pam_pwhistory - PAM module to remember last passwords
  .SH "SYNOPSIS"
    .HP u
      pam_pwhistory.so
       [debug]
       [use_authtok]
       [enforce_for_root]
       [remember=N]
       [retry=N]
       [authtok_type=STRING]
       [file=/path/filename]
       [conf=/path/to/config-file]

  .SH "DESCRIPTION"

    .PP This module saves the last passwords for each user in order to force password change history and keep the user from alternating between the same password too frequently.
    .PP This module does not work together with kerberos. In general, it does not make much sense to use this module in conjunction with NIS or LDAP, since the old passwords are stored on the local machine and are not available on another machine for password history checking.

  .SH "OPTIONS"

      .PP debug

              Turns on debugging via syslog(3).

          .RE
          .PP use_authtok

                  When password changing enforce the module to use the new password provided by a previously stacked password module (this is used in the example of the stacking of the pam_passwdqc module documented below).

              .RE
              .PP enforce_for_root

                      If this option is set, the check is enforced for root, too.

                  .RE
                  .PP remember=N

                          The last N passwords for each user are saved. The default is 10. Value of 0 makes the module to keep the existing contents of the opasswd file unchanged.

                      .RE
                      .PP retry=N

                                Prompt user at most N times before returning with error. The default is 1.

                            .RE
                            .PP authtok_type=STRING

                                    See pam_get_authtok(3) for more details.

                                .RE
                                .PP file=/path/filename

                                        Store password history in file /path/filename rather than the default location. The default location is /etc/security/opasswd.

                                    .RE
                                    .PP conf=/path/to/config-file

                                            Use another configuration file instead of the default /etc/security/pwhistory.conf.

                                        .RE

                                    .PP The options for configuring the module behavior are described in the pwhistory.conf(5) manual page. The options specified on the module command line override the values from the configuration file.

                                  .SH "MODULE TYPES PROVIDED"

                                    .PP Only the password module type is provided.

                                  .SH "RETURN VALUES"

                                      .PP PAM_AUTHTOK_ERR

                                              No new password was entered, the user aborted password change or new password couldn't be set.

                                          .RE
                                          .PP PAM_IGNORE

                                                  Password history was disabled.

                                              .RE
                                              .PP PAM_MAXTRIES

                                                      Password was rejected too often.

                                                  .RE
                                                  .PP PAM_USER_UNKNOWN

                                                          User is not known to system.

                                                      .RE

                                                  .SH "EXAMPLES"

                                                    .PP An example password section would be:

                                                    #%PAM-1.0
                                                    password     required       pam_pwhistory.so
                                                    password     required       pam_unix.so        use_authtok

                                                    .PP In combination with pam_passwdqc:

                                                    #%PAM-1.0
                                                    password     required       pam_passwdqc.so    config=/etc/passwdqc.conf
                                                    password     required       pam_pwhistory.so   use_authtok
                                                    password     required       pam_unix.so        use_authtok

                                                  .SH "FILES"

                                                      .PP /etc/security/opasswd

                                                              Default file with password history

                                                          .RE
                                                          .PP /etc/security/pwhistory.conf

                                                                  Config file for pam_pwhistory options

                                                              .RE
                                                              .PP /usr/share/pam/security/pwhistory.conf

                                                                      Config file for pam_pwhistory options. It will be used if /etc/security/pwhistory.conf does not exist.

                                                                  .RE

                                                              .SH "SEE ALSO"

                                                                .PP pwhistory.conf(5), pam.conf(5), pam.d(5), pam(8) pam_get_authtok(3)

                                                              .SH "AUTHOR"

                                                                  .PP pam_pwhistory was written by Thorsten Kukuk <kukuk@thkukuk.de>