NIS (yp)
NIS (Network Information System) in the current name for what was once
known as yp (Yellow Pages). The purpose of NIS is to allow many
machines on a network to share configuration information, including
password data. NIS is not designed to promote system security. If
your system uses NIS you will have a very short /etc/passwd file that
includes a line that looks like this:
+::0:0:::i
To view the real password file use this command `ypcat passwd`
NIS and NIS+ are being replaced by LDAP (Lightweight Directory Access Protocol).
|
|
- How to Change a Unix Password
To change your Unix password, use the `passwd` command. Unless you are the “root” user, you will need to know your current password to set a new one. If you have forgotten your current password, you will need to contact the “root” user to have your password reset. Here is an example of the user [...]...
- How to List Unix Users
List Logged In Unix Users Unix has many commands to list users who are logged in. These commands include ‘w,’ ‘who,’ and ‘users:’ $ w 9:51PM up 99 days, 5:39, 2 users, load averages: 0.83, 0.90, 0.90 USER TTY FROM LOGIN@ IDLE WHAT will p0 c-66-164-235-73. 8:11AM - w spencer p3 c-66-164-235-73. 8:26PM 1:24 pine [...]...
- Password Aging
Password aging forces the user to change passwords after a system administrator-specified period of time. Password aging can also force a user to keep a password for a certain number of weeks before changing it. Sample entry from /etc/passwd with password aging installed: will:5fg63fhD3d,M.z8:9406:12:Will Spencer:/home/will:/bin/bash Note the comma in the encrypted password field. The characters [...]...
- How to Audit Unix Passwords
To audit Unix passwords, you must compare each encrypted password in the Unix password file with a set of potential encrypted passwords. These potential encrypted passwords are created by encrypting every password in a list of plaintext passwords. This is an example of a dictionary attack. The Unix passwd File Location The traditional location for [...]...
- How to Change Your Shell
Under some version of Unix, users can use the `chsh` or `passwd -e` commands to edit the shell configured for their account in the passwd file. Under other Unix variants, only the root user can use these commands. Your shell is defined in the last field of the password file. If you have “root” privileges, you [...]...