6.25. pam_pwhistory - grant access using .pwhistory file
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## 6.25. pam_pwhistory - grant access using .pwhistory file

`pam_pwhistory.so` [ debug ] [ use_authtok ] [ enforce_for_root ] [ remember=`N` ] [ retry=`N` ] [ authtok_type=`STRING` ]

### 6.25.1. DESCRIPTION

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.

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.

### 6.25.2. OPTIONS

`debug`

  Turns on debugging via syslog(3).

`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_cracklib module documented below).

`enforce_for_root`

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

`remember=`N``

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

`retry=`N``

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

`authtok_type=`STRING``

  See pam_get_authtok(3) for more details.

### 6.25.3. MODULE TYPES PROVIDED

Only the `password` module type is provided.

### 6.25.4. RETURN VALUES

PAM_AUTHTOK_ERR

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

PAM_IGNORE

  Password history was disabled.

PAM_MAXTRIES

  Password was rejected too often.

PAM_USER_UNKNOWN

  User is not known to system.

### 6.25.5. FILES

`/etc/security/opasswd`

  File with password history

### 6.25.6. EXAMPLES

An example password section would be:

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

In combination with pam_cracklib:

    #%PAM-1.0
    password     required       pam_cracklib.so    retry=3
    password     required       pam_pwhistory.so   use_authtok
    password     required       pam_unix.so        use_authtok

### 6.25.7. AUTHOR

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

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