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From: rdc30med@nmrdc1.nmrdc.nnmc.navy.mil (LCDR Michael E. Dobson)
Newsgroups: comp.unix.admin,comp.unix.shell
Subject: Re: Logging a User Off
Message-ID: <1990Sep12.193848.6167@nmrdc1.nmrdc.nnmc.navy.mil>
Date: 12 Sep 90 19:38:48 GMT
References: <1990Sep11.173008.274@mccc.uucp> <544@fciva.FRANKLIN.COM>
Organization: Naval Medical Research & Development Command
Lines: 25

In article <544@fciva.FRANKLIN.COM> dag@fciva.UUCP (Daniel A. Graifer) writes:
>
>I believe the passwd mechanism supported this before the options for managing
>it were added to /bin/passwd.  You should find the file format for /etc/passwd
>(I believe it is in section 4 of the Programmer's Reference Manual).  There is
>some combination of characters which are not valid encryption results (ex. ",",
>".", and "/") that are appended to the encrypted password field.  I forget 
>where the 'last change date' is stored.

It indeed does.  A ',' after the encryption field defines the beginning of
the passwd aging and last changed fields.  It is stored as four alphanumeric
values, the first two being the min and max password age values and the last 
two defining the last changed date.

On my system, all new users have ',B3' in the passwd field of /etc/passwd.  
This forces all new users to assign a password at first login and they can't 
by-pass it.  It also forces them to choose a new password every 120 days and 
prevents them from changing for 30 days after the last change.  See the passwd 
man page on Sys V for details and what the field values mean.

-- 
Mike Dobson, Sys Admin for      | Internet: rdc30med@nmrdc1.nmrdc.nnmc.navy.mil
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