passwd(5) [redhat man page]

PASSWD(5)							   File formats 							 PASSWD(5)

NAME

       passwd - password file

DESCRIPTION

       Passwd  is  a text file, that contains a list of the system's accounts, giving for each account some useful information like user ID, group
       ID, home directory, shell, etc.	Often, it also contains the encrypted passwords for each account.  It should have general read	permission
       (many utilities, like ls(1) use it to map user IDs to user names), but write access only for the superuser.

       In  the	good old days there was no great problem with this general read permission.  Everybody could read the encrypted passwords, but the
       hardware was too slow to crack a well-chosen password, and moreover, the basic assumption used to be that  of  a  friendly  user-community.
       These  days  many  people  run some version of the shadow password suite, where /etc/passwd has *'s instead of encrypted passwords, and the
       encrypted passwords are in /etc/shadow which is readable by the superuser only.

       Regardless of whether shadow passwords are used, many sysadmins use a star in the encrypted password field to make sure that this user  can
       not authenticate him- or herself using a password. (But see the Notes below.)

       If you create a new login, first put a star in the password field, then use passwd(1) to set it.

       There is one entry per line, and each line has the format:

	      account:password:UID:GID:GECOS:directory:shell

       The field descriptions are:

	      account	the name of the user on the system.  It should not contain capital letters.

	      password	the encrypted user password or a star.

	      UID	the numerical user ID.

	      GID	the numerical primary group ID for this user.

	      GECOS	This  field  is  optional and only used for informational purposes.  Usually, it contains the full user name.  GECOS means
			General Electric Comprehensive Operating System, which has been renamed to GCOS when GE's large systems division was  sold
			to Honeywell.  Dennis Ritchie has reported: "Sometimes we sent printer output or batch jobs to the GCOS machine.  The gcos
			field in the password file was a place to stash the information for the $IDENTcard.  Not elegant."

	      directory the user's $HOME directory.

	      shell	the program to run at login (if empty, use /bin/sh).  If set to a non-existing executable, the	user  will  be	unable	to
			login through login(1).

NOTE

       If you want to create user groups, their GIDs must be equal and there must be an entry in /etc/group, or no group will exist.

       If  the	encrypted  password  is  set  to a star, the user will be unable to login using login(1), but may still login using rlogin(1), run
       existing processes and initiate new ones through rsh(1), cron(1), at(1), or mail filters, etc.  Trying to lock an account by simply  chang-
       ing the shell field yields the same result and additionally allows the use of su(1).

FILES

       /etc/passwd

SEE ALSO

       passwd(1), login(1), su(1), group(5), shadow(5)

								    1998-01-05								 PASSWD(5)

d_passwd(4)							   File Formats 						       d_passwd(4)

NAME

       d_passwd - dial-up password file

SYNOPSIS

       /etc/d_passwd

DESCRIPTION

       A  dial-up  password is an additional password required of users who access the computer through a modem or dial-up port. The correct pass-
       word must be entered before the user is granted access to the computer.

       d_passwd is an ASCII file which contains a list of executable programs (typically shells) that require a dial-up password and  the  associ-
       ated encrypted passwords. When a user attempts to log in on any of the ports listed in the dialups file (see dialups(4)), the login program
       looks at the user's login entry stored in the passwd file (see passwd(4)), and compares the login shell field to the entries  in  d_passwd.
       These entries determine whether the user will be required to supply a dial-up password.

       Each entry in d_passwd is a single line of the form:

	 login-shell:password:

       where

       login-shell    The name of the login program that will require an additional dial-up password.

       password       An  encrypted password. Users accessing the computer through a  dial-up port or modem using login-shell  will be required to
		      enter this password before gaining access to the computer.

       d_passwd should be owned by the root user and the root group. The file should have read and write permissions for the owner (root) only.

       If the user's login program in the passwd file is not found in d_passwd or if the login shell field in passwd is empty, the user must  sup-
       ply  the  default  password.  The default password is the entry for /usr/bin/sh. If d_passwd has no entry for /usr/bin/sh, then those users
       whose login shell field in passwd is empty or does not match any entry in d_passwd will not be prompted for a dial-up password.

       Dial-up logins are disabled if d_passwd has only the following entry:

	 /usr/bin/sh:*:

EXAMPLES

       Example 1 Sample d_passwd file.

       Here is a sample d_passwd file:

	 /usr/lib/uucp/uucico:q.mJzTnu8icF0:
	 /usr/bin/csh:6k/7KCFRPNVXg:
	 /usr/bin/ksh:9df/FDf.4jkRt:
	 /usr/bin/sh:41FuGVzGcDJlw:

   Generating An Encrypted Password
       The passwd (see passwd(1)) utility can be used to generate the encrypted password for each login program. passwd generates encrypted  pass-
       words  for  users  and places the password in the shadow (see shadow(4)) file. Passwords for the d_passwd file will need to be generated by
       first adding a temporary user id using useradd (see useradd(1M)), and then using passwd(1) to generate the desired password in  the  shadow
       file. Once the encrypted version of the password has been created, it can be copied to the d_passwd file.

       For example:

	   1.	  Type useradd tempuser and press Return. This creates a user named tempuser.

	   2.	  Type passwd tempuser and press Return. This creates an encrypted password for tempuser and places it in the shadow file.

	   3.	  Find the entry for tempuser in the shadow file and copy the encrypted password to the desired entry in the d_passwd file.

	   4.	  Type userdel tempuser and press Return to delete tempuser.

       These steps must be executed as the root user.

FILES

       /etc/d_passwd	dial-up password file

       /etc/dialups	list of dial-up ports requiring dial-up passwords

       /etc/passwd	password file

       /etc/shadow	shadow password file

SEE ALSO

       passwd(1), useradd(1M), dialups(4), passwd(4), shadow(4)

WARNINGS

       When  creating  a  new  dial-up password, be sure to remain logged in on at least one terminal while testing the new password. This ensures
       that there is an available terminal from which you can correct any mistakes that were made when the new password was added.

SunOS 5.11							    2 Sep 2004							       d_passwd(4)