CT320

CT320: Network and System Administration

Fall 2015

Accounts

See this page as a slide show

CT320: Network and System Administration

Accounts and Namespaces

Thanks to Dr. James Walden, NKU, Russ Wakefield, CSU, and Dr. Indrajit Ray, CSU, for contents of these slides

Topics

  1. UNIX User Accounts
  2. Passwords
  3. User Management
  4. Namespaces

UNIX Accounts

/etc/passwd, /etc/shadow

Central file(s) describing UNIX user accounts.

/etc/passwd/etc/shadow
UsernameUsername
xEncrypted password
UIDDate of last pw change
Default GIDDays until change allowed
GCOSDays until change required
Home directoryExpiration warning time
Login shellExpiration date
    student:x:1000:1000:Example User,,555-1212,:/home/student:/bin/bash
    student:$1$w/UuKtLF$otSSvXtSN/xJzUOGFElNz0:13226:0:99999:7:::

Username

UIDs

Password

Encrypted Password

xno password here, it’s in /etc/shadow
*login forbidden
nothingno password needed
$1$salt$hashMD5
$2a$salt$hashBlowfish
$2y$salt$hashBlowfish (correct handling of 8-bit chars)
$3$salt$hashNT LAN Manager hash algorithm
$4$salt$hashSHA-1
$5$salt$hashSHA-256
$6$salt$hashSHA-512
13-char stringoriginal DES hashing algorithm

GID

    wheel:x:10:root,waldenj,bergs

GECOS

Home Directory

Login Shell

Adding a User

  1. Create account with adduser.
  2. Lock account until user arrives.
  3. User signs account agreement.
  4. Set password with the passwd command.

Adding a User

Disabling an Account

Removing a User

Namespaces

Systems include many namespaces:

Types of Namespaces

Namespace Problems

Name Selection

Name Lifetime

Namespace Scope

Key Points

Modified: 2015-09-19T17:23

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